Oki ML520 manual

Page: 1 Service Guide ML520/521 Chapter 0 About This Manual ML520 // ML521 Dot Matrix Printers Adobe Acrobat printable reference copy of the OKIDATA Service Training Manual. 09/17/97 Note: This Adobe Acrobat version of the Okidata Service Training Manual was built with the pictures rendered at 300 dpi, which is ideal for printing, but does not view[...]

Table of Contents Page Service Guide ML520/521 0 About This Manual Front Cover 1 Copyright Information 2 1 Product Specifications 1.1.01 General Information 3 ....1.2 Physical Specifications 4 ....1.3 Power Requirements 5 ....1.4 Environmental Conditions 6 ....1.5 Agency Approvals 7 ....1.6 Operational Specifications 8 ....1.7 Paper Specifications [...]

Table of Contents Page ........Head Drive Time 39 ........Print Speed 40 ........%Head Overheat Alarm Processing 41 ....2.1.08 Power Supply Circuit 42 2.2 Mechanical Operation - Printhead Mechanism 43 ........Printhead Gap Information 44 ........Interconnect Diagram: Control Board to Printhead 45 ........Line Feed Motor Resistance 46 ........Space [...]

Table of Contents Page ....3.2.11 Space Motor and Roller Guide Assemblies 80 ....3.2.12 Carriage Cable 81 ....3.2.13 Space Rack 82 ....3.2.14 Roller/Holder Backup Assembly 83 ....3.2.15 Guide Rail and Adjust Cam 84 ....3.2.16 Left Ground Plate 85 ....3.2.17 Right Ground Plate 86 ....3.2.18 Rear and Cut Sheet Paper Feed Sensor Levers 87 ....3.2.19 P[...]

Table of Contents Page ....4.4.04 Tips for Preventing Image Problems 123 ....4.4.05 Common Problems 124 4.5 Abnormal Output - Output Samples 125 ....Left Margin Drifting Problem 126 4.6 Fault Alarms 127 ....4.6.02 ALARM/LED Display Troubleshooting Table Index 128 ....4.6.03 ALARM/LED Display Troubleshooting Tables 129 4.7 Repair Analysis Procedures[...]

Table of Contents Page ........Format 165 ........Current Part Numbers 166 ....B.1.02 Definition of Terms 167 ....B.1.03 Parts Ordering Information 168 B.2 Charts 169 ........Overview 170 ....B.2.01 Printer 171 ....B.2.02 Upper Cover Assembly 172 ....B.2.03 Printer General Assembly 173 ....B.2.04 Printer Unit 174 ....B.2.05 Printer Unit 175 ....B.2[...]

Page: 2 Service Guide ML520/521 Chapter 0 About This Manual This document may not be reproduced without the written permission of the Okidata Technical Training Group. Every effort has been made to ensure the accuracy of the information contained in this training course. Okidata is not responsible for errors beyond its control. © 1994 by Okidata A[...]

Proprinter is a registered trademark of International Business Machine Corporation. Windows is a trademark of Microsoft Corporation Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 3 Service Guide ML520/521 Chapter 1 Product Specifications 1.1.01 General Information The Microline 520 and Microline 521 are letter quality, nine-pin, dot-matrix printers which utilize OKISMART paper handling. Patented Okidata technology does away with the manual head gap adjustment. The printer actually reads and learns the print medium bei[...]

Page: 4 Service Guide ML520/521 Chapter 1 Product Specifications 1.2 PHYSICAL SPECIFICATIONS 1.2.01 Dimensions NOTE: Dimensions INCLUDE the platen knob, acoustic cover, and paper separator. Microline 520 Width: 16.9 inches (43 centimeters) Depth: 14.9 inches (37.8 centimeters) Height: 6.5 inches (16.5 centimeters) Microline 521 Width: 23 inches (58[...]

Page: 5 Service Guide ML520/521 Chapter 1 Product Specifications 1.3 POWER REQUIREMENTS 1.3.01 Input Power 120 VAC: +5.5 / -15% 230/240 VAC: +10 / -14% 1.3.02 Power Consumption Operating: 110 VA Idle: 40 VA Local Test: 70 VA 1.3.03 Power Frequency 120 VAC: 60 Hz +/- 2% 230/240 VAC: 50/60 Hz +/- 2% Copyright 1997, Okidata, Division of OKI America, I[...]

Page: 6 Service Guide ML520/521 Chapter 1 Product Specifications 1.4 ENVIRONMENTAL CONDITIONS 1.4.01 Acoustic Rating Near Letter Quality Mode Microline 520 54.9 dBA Microline 521 54.4 dBA Utility Mode Microline 520 57.2 dBA Microline 521 56.9 dBA Quiet Mode Microline 520 52.5 dBA Microline 521 52.3 dBA 1.4.01 Altitude 10,000 feet (3,050 meters) 1.4[...]

Page: 7 Service Guide ML520/521 Chapter 1 Product Specifications 1.5 AGENCY APPROVALS 1.5.01 Listings UL No: UL Standard No. 1950 D3 CSA No: CSA Standard 22.2-950 D3 FCC: FCC Certified per Part 15, Subject J, Class B IEC: IEC 950 VDE: VDE 0805 VDE 0875 Class B BS: BS 7002 Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. S[...]

Page: 8 Service Guide ML520/521 Chapter 1 Product Specifications 1.6 OPERATIONAL SPECIFICATIONS 1.6.01 Character Matrix Sizes Table of Print Speed and Character Matrix Mode Near Letter Quality Utility High Speed Draft Speed 80 (12cpi) 320 (12cpi) 427 (12cpi) Matrix (H x V) 17 x 13 9 x 7 7 x 7 Print Speed at Different CPI for the ML 520/521 Mode CPI[...]

Characters Per Line Characters Per Inch 80 10 96 12 120 15 137 17.1 160 20 Microline 521 Characters Per Line Characters Per Inch 136 10 163 12 204 15 233 17.1 272 20 1.6.03 Character Pitches 5, 6, 8.5, 10, 12, 15, 17.1, 20 1.6.04 Character Sets Standard ASCII EPSON Character Set I & II IBM Character Set I, II & All Characters Foreign Charac[...]

1.6.05 Emulations NOTE: The emulations are co-resident Epson FX IBM Proprinter Microline Standard 1.6.06 Fonts Near Letter Quality Courier Utility Gothic High Speed Draft Gothic Bar Code Code 39 UPC A UPC E EAN 8 EAN 13 Interleaved 2 of 5 Code 128 (A, B, C) Postnet 1.6.07 Front Panel Switches SELECT / Menu Micro Feed Up / Down Shift Paper Park Line[...]

RS232C Serial 1.6.10 Line Feed Increments Fixed 6 lines per inch (lpi) [0.167 inch (4.23 millimeters)] 8 lines per inch (lpi) [0.125 inch (3.175 millimeters)] Variable n/60 inch n/72 inch n/144 inch n/216 inch 1.6.11 Line Feed Time 65 milliseconds 6 lines per inch (lpi) 6 milliseconds 8 lines per inch (lpi) 1 second 5.0 inches (Continuous paper fee[...]

Paper Park Automatic Paper Loading Forms Tear Off 1.6.15 Paper Loading Auto Loading (Top Feed) Press FORM FEED / Load switch to feed paper to default position 1.6.16 Paper Out Detection Distance from end of paper Rear Feed: 0.5 inches (12.7 mm) Bottom Feed: 0.5 inches (12.7 mm) Top Feed: 0.5 inches (12.7 mm) 1.6.17 Paper Tear Capabilities Forms Tea[...]

1. Printhead Gap Adjustment This is a SERVICE ADJUSTMENT made by a technician. It is covered in Section 3.3 of this Service Handbook. The Adjustment measures 0.014 +/- 0.001 inches 90.35, +/-0.03 mm). 2. Printhead Gap Adjustment This is a MENU ITEM in the SET-UP Group. It fine tunes the automatic setting of the printhead gap. The settings are 0, 1 [...]

Used when the same paper is used ALL of the time. Bypasses the automatic head gap adjustment. 1 is the narrowest head setting. 9 is the widest head setting. 1.6.19 Print Modes Near Letter Quality Utility High Speed Draft 1.6.20 Print Speed Table of Print Speed and Character Matrix Mode Near Letter Quality Utility High Speed Draft Speed 80 (12 cpi) [...]

Page: 9 Service Guide ML520/521 Chapter 1 Product Specifications 1.7 PAPER SPECIFICATIONS CAUTION: Use Bottom Feed and/or optional Pull Tractor for card stock and labels. 1.7.01 Types Card Stock Weight: 120 lbs. (450 g/m 2 ) Maximum Width: Microline 520 5 to 8 inches (12.7 to 20.3 centimeters) Microline 521 5 to 14 inches (12.7 to 35.6 centimeters)[...]

Width: 7.2 to 14.3 inches (18.3 to 36.3 centimeters) Width: Microline 520 7.2 to 8.5 inches (18.2 to 21.5 centimeters) Microline 521 7.2 to 14.3 inches (18.2 to 36.3 centimeters) Length: 3 to 17 inches (7.62 to 43.18 centimeters) Thickness: 0.014 inches (0.325 millimeters) Maximum Paper Feed Path: Top Printhead Gap Information: Refer to the Printhe[...]

NOTE: Roller marks may mar the transparency under high temperature / high humidity conditions. Weight: 12 to 24 lbs. (45 to 90 g/m 2 ) Width: Microline 520 7.2 to 8.5 inches (18.2 to 21.5 centimeters) Microline 521 7.2 to 14.3 inches (18.2 to 36.3 centimeters) Length: 3 to 17 inches (7.62 to 43.18 centimeters) Thickness: 0.14 inches (0.36 millimete[...]

NOTE: The recommended weight is specific to paper type. Minimum: 9 lb. (35 g/m 2 ) Maximum: 120 lb. (90 g/m 2 ) 1.7.06 Width NOTE: The recommended width is specific to paper type. Paper Microline 520 Minimum: 3.5 inches ( 8.8 centimeters) Maximum: 10.5 inches (26.6 centimeters) Microline 521 Minimum: 3.5 inches ( 8.8 centimeters) Maximum: 16.5 inch[...]

Page: 10 Service Guide ML520/521 Chapter 1 Product Specifications 1.8 MEMORY SPECIFICATIONS 1.8.01 EEPROM 1 Kbit serial EEPROM (used to store Menu data) 1.8.02 EPROM 1 MBit EPROM (Printer Control Program - Fonts) 1.8.03 RAM 128 Kbyte Total Resident RAM Used as Receive Buffer Receive Buffer Size is selected through the Menu. Settings are: 64 K, 32 K[...]

Page: 11 Service Guide ML520/521 Chapter 1 Product Specifications 1.9 CONSUMABLES 1.9.01 Ribbon CAUTION: Using a non-Okidata ribbon may damage the printhead and void any warranties. Material Nylon fabric, cartridge type, re-inking Type Black Ribbon Life (On average, at 10 characters per inch, Utility Mode) 4 million characters Copyright 1997, Okida[...]

Page: 12 Service Guide ML520/521 Chapter 1 Product Specifications 1.10 OPTIONS - Cut Sheet Feeders 1.10.01 Cut Sheet Feeders Single Bin The CSF-5000 is a narrow feeder for the Microline 520. Single Bin with envelope capability Paper Width: 7.2" to 8.5" (18.3 cm to 36.3 cm) Paper Length: 10.1" to 14" (25.6 cm to 35.6 cm) Capacity[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 13 Service Guide ML520/521 Chapter 1 Product Specifications 1.10.02 Pull Tractor Kit NOTE: The Pull Tractor Kit (P/N 70023001) is a narrow feeder for the Microline 520. The Pull Tractor Kit (P/N 70023201) is a wide feeder for the Microline 521. Bottom Feed Rear Feed (For Push/Pull Operation) Paper Types: Continuous Feed and Labels Copyright 1[...]

Page: 14 Service Guide ML520/521 Chapter 1 Product Specifications 1.10.04 Bottom Push Tractor Kit NOTE: The Bottom Push Tractor Kit (P/N 70022901) is a narrow feeder for the Microline 520. The Bottom Push Tractor Kit (P/N 70023101) is a wide feeder for the Microline 521. Bottom Feed Paper Type: Continuous Feed Includes: Stand and Metal Tear Bar Cop[...]

Page: 15 Service Guide ML520/521 Chapter 1 Product Specifications 1.10.05 Serial Interface Super-Speed 19.2K RS-232C Ready/Busy/X-On/X-Off Protocols Can be configured through the Menu or OKISmart Utility Program Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any update[...]

Page: 16 Service Guide ML520/521 Chapter 1 Product Specifications 1.10.06 Roll Paper Stand Adapts printer for use with roll-type paper (Model 520 only) Includes: Stand, Support, Cord and DIN plug for connection to printer Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for [...]

Page: 17 Service Guide ML520/521 Chapter 1 Product Specifications 1.10.08 OKISmart Typer Utility Obtained via BRC (Business Reply Card) packaged with printer Includes: Typewriter Mode, Form Creation Utility and Barcode Utility 1.10.09 OKISmart Panel Utility Obtained via BRC (Business Reply Card) packaged with printer Includes: Front Panel Control U[...]

Page: 18 Service Guide ML520/521 Chapter 1 Product Specifications 1.11 RELIABILITY 1.11.01 Mean Time Before Failure (MTBF) Approximately 6,000 hours: 25% duty cycle / 35% page density 1.11.02 Mean Time To Repair (MTTR) Approximately 15 minutes to major sub-assembly level 1.11.03 Printer Life Approximately 16,000 hours of power-on time: 25% duty cyc[...]

Page: 19 Service Guide ML520/521 Chapter 2 Principles of Operation 2.1 ELECTRICAL OPERATION The printer is comprised of the electrical components listed below. Main Control Board Power Supply Assembly Transformer Filter Board Operator Panel Space Motor / Line Feed Motor Printhead Copyright 1997, Okidata, Division of OKI America, Inc. All rights res[...]

Page: 20 Service Guide ML520/521 Chapter 2 Principles of Operation 2.1.01 Main Control Board The main control board is made up of the microprocessor, peripheral circuits, drive circuits, sensors and interface connectors. The power to the main control board is supplied by the transformer assembly through a wire harness. The power to other electrical[...]

Page: 21 Service Guide ML520/521 Chapter 2 Principles of Operation Block Diagram Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 22 Service Guide ML520/521 Chapter 2 Principles of Operation Program ROM Location 05CA: 27C1024 This 64k x 16 bit (1Mbit) EPROM contains the control program for the printer. The MPU executes the instructions contained in this program. The Program ROM is assigned to the program memory area of the MPU and instructions are fetched by the PSEN si[...]

Page: 23 Service Guide ML520/521 Chapter 2 Principles of Operation RAM Location 05CB: 511664Z The RAM is CMOS dynamic RAM with 65,536 words x 16-bit configuration. It is used as a receive buffer, print buffer and work buffer. Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) [...]

Page: 24 Service Guide ML520/521 Chapter 2 Principles of Operation LSI Location 04B: MSM79VO35 Detects the output of the two-phase sensor on the DC space motor to control the motor drive phase. Transmits and receives serial data to and from the printhead based on the dot timing (which is derived from the space motor speed). Controls the external in[...]

Page: 25 Service Guide ML520/521 Chapter 2 Principles of Operation Electrically Erasable Programmable Read Only Memory (EEPROM) (Location 03C: 93CS46) The EEPROM is a CMOS serial I/O type memory (EEPROM). It is capable of electrically erasing and writing 1,024 bits. The EEPROM contains the menu data and the head drive time correction data. Copyrigh[...]

Page: 26 Service Guide ML520/521 Chapter 2 Principles of Operation 2.1.02 Initialization This printer is initialized when the printer is powered on or when the I-PRIME-N signal is input from the host via the parallel interface. The steps in Printer Initialization are listed below. The RST-N signal is output from the reset circuit to reset the MPU a[...]

Page: 27 Service Guide ML520/521 Chapter 2 Principles of Operation 2.1.03 Parallel Interface Control The parallel data input from the host to the interface LSI is latched to the internal register at the falling edge of the STROBE-N signal. The LSI sets the BUSY-N signal to inform the host that the data is being processed. The LSI also outputs the R[...]

Page: 28 Service Guide ML520/521 Chapter 2 Principles of Operation 2.1.04 Print Control The print data is transmitted as serial data from the LSI to the control circuit and the driver contained in the printhead. After the data is printed, the sensor analog circuit controlling each pin returns the pin stroke data to the MPU. The MPU will make an aut[...]

Page: 29 Service Guide ML520/521 Chapter 2 Principles of Operation LSI/Printhead Interface The connection between the LSI and the printhead is made with the bi-directional serial data bus. The LSI transmits the print data as serial data to the logic circuit of the printhead. The printhead returns serial data from the printhead sensor analog circuit[...]

Page: 30 Service Guide ML520/521 Chapter 2 Principles of Operation Gap Adjust Control The Gap Adjust LSI receives stroke length information for all of the printhead pins from the sensor analog circuit. The Gap Adjust LSI then sets the optimum printhead gap for the printing medium. NOTE: Refer to Section 2.2.03 for a description of the mechanical pr[...]

Page: 31 Service Guide ML520/521 Chapter 2 Principles of Operation Print Compensation Control The printhead compensates for the shape of the platen as shown below. NOTE: Also refer to Section 2.1.07 - Head Drive Time Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any u[...]

Page: 32 Service Guide ML520/521 Chapter 2 Principles of Operation 2.1.05 Space and Line Feed (SP/LF) Motor Control The LSI (Location 04B: MSM79V035) generates the space motor and the line feed motor control signals according to commands received from the MPU. These signals are sent to the SP/LF motor driver. Copyright 1997, Okidata, Division of OK[...]

Page: 33 Service Guide ML520/521 Chapter 2 Principles of Operation Line Feed Motor Control The SP/LF motor driver (Location 5A: MHM2025) drives the line feed motor in two-phase bipolar, based on the phase changeover data output from the LSI. The serial data from the LSI (04B: MSM79V035) is processed by a register contained in the SP/LF motor driver[...]

Page: 34 Service Guide ML520/521 Chapter 2 Principles of Operation Space Motor Control The SP/LF motor driver (Location 5A: MHM2025) drives the three-phase brushless motor. Motor movement is based on the phase signal (SPU, SPV and SPW) and the speed instruction data from the LSI. The MPU can identify the current speed of the space motor by measurin[...]

Page: 35 Service Guide ML520/521 Chapter 2 Principles of Operation Encoder Disk As the space motor operates, the encoder disk spins. When the encoder disk interrupts the photo sensors, the signals Phase A and Phase B are generated. The LSI (Location 04B: MSM79V035) divides these edge pulse signals (the frequency division is based on the selected pr[...]

Page: 36 Service Guide ML520/521 Chapter 2 Principles of Operation 2.1.06 Operation Panel The Serial I/O Port (Ports 20 - 23) of the MPU reads the operation panel switch data from the operation panel control LSI (Location IC1: BUS148S). A two byte (15 bits +1 parity bit (even parity)) command (OPTXD) is transmitted from the MPU to the operation pan[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 37 Service Guide ML520/521 Chapter 2 Principles of Operation 2.1.07 Alarm Circuit Driver Circuit Alarm Processing The printhead driver output and the head gap magnet output drive signals are monitored at R29 and C8. The POWER OFF-P signal is output by the comparator (Location 02C: IC2901) when driven for more than the specified time. This sig[...]

Page: 38 Service Guide ML520/521 Chapter 2 Principles of Operation Low Motor Drive Voltage Alarm +40V is converted into the POWLEV signal (0 vdc to +5 vdc) by the voltage divider network of R542 and R544, then input to the A/D port of the MPU. The value of this voltage is used to control the drive time and the print speed (pass number) of the head.[...]

Page: 39 Service Guide ML520/521 Chapter 2 Principles of Operation Head Drive Time The head drive time is modified to compensate for the amount of the voltage drop of the POWLEV signal. By monitoring the voltage drop every 500 microseconds, the MPU is able to control and maintain the impact necessary for each printhead pin. Copyright 1997, Okidata,[...]

Page: 40 Service Guide ML520/521 Chapter 2 Principles of Operation Print Speed Actual Voltage (+40 vdc) Passes Required Relative Print Speed +34 vdc or greater 1 100% +32 vdc to +34 vdc 1 Approximately 85% +30 vdc to +32 vdc 1 Approximately 50% +30 vdc or less 2 Less than 50% Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserve[...]

Page: 41 Service Guide ML520/521 Chapter 2 Principles of Operation Head Overheat Alarm Processing If the printhead temperature exceeds 110 degrees Celsius, the printer will switch to uni-directional print. If the temperature exceeds 118 degrees Celsius, printing will stop. Once the printhead cools, printing will resume. Two thermistors are used to [...]

Page: 42 Service Guide ML520/521 Chapter 2 Principles of Operation 2.1.08 Power Supply Circuit The switching type power supply circuit supplies the +5 vdc, +/-8 vdc, 10 VAC and +40 vdc. Voltage/Signal Purpose +5 vdc IC logic levels, LED drive voltages +8 vdc Serial interface line voltage, comparator IC +10 VAC Serial interface line voltage and the [...]

Page: 43 Service Guide ML520/521 Chapter 2 Principles of Operation 2.2 MECHANICAL OPERATION 2.2.01 Printhead Mechanism The printhead is a spring-charged, 9-pin printhead. It is attached to the carriage, which moves parallel to the platen. Electrically, the printhead is controlled by the main control board via the carriage cable and the space motor.[...]

Page: 44 Service Guide ML520/521 Chapter 2 Principles of Operation Printhead Gap Information Three items factor into printhead gap information. 1. Printhead Gap Adjustment This is a SERVICE ADJUSTMENT made by a technician. It is covered in Section 3.3 of this Service Handbook. The Adjustment measures 0.014, +/- 0.001 inches (0.35, +/- 0.03 mm). 2. [...]

Semi Auto Gap Similar to Auto Gap. Automatically determines paper thickness of the first page. During single-sheet feed, each pages thickness IS NOT checked while a job is printing. 1, 2, 3, 4, 5, 6, 7, 8, 9 Used when the same paper is used ALL of the time. Bypasses the automatic head gap adjustment. 1 is the narrowest gap setting. 9 is the widest [...]

Page: 45 Service Guide ML520/521 Chapter 2 Principles of Operation Interconnect Diagram: Control Board to Printhead NOTE: The printhead coil resistance values ARE NOT LISTED. The individual printwire control lines CANNOT be accessed on this printhead. Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Busine[...]

Page: 46 Service Guide ML520/521 Chapter 2 Principles of Operation Line Feed Motor Resistance The resistance of each coil should be approximately 13 ohms. Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 47 Service Guide ML520/521 Chapter 2 Principles of Operation Space Motor Resistance The resistance of each coil should be approximately 5 ohms. Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 48 Service Guide ML520/521 Chapter 2 Principles of Operation Printhead Operation When the printhead is idle, the armature is attracted to the permanent magnet. The print wires, which are attached to each armature, are then concealed inside the wire guide. When a signal to print a character is received, current flows through a coil. The magnet[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 49 Service Guide ML520/521 Chapter 2 Principles of Operation Printhead Temperature If the printhead temperature exceeds 110 degrees Celsius, the printer will switch to uni-directional print. If the temperature exceeds 118 degrees Celsius, printing will stop. Once the printhead cools, printing will resume. Two thermistors are used to monitor t[...]

Page: 50 Service Guide ML520/521 Chapter 2 Principles of Operation 2.2.02 Spacing Mechanism The spacing mechanism consists of a carriage shaft (mounted parallel to the platen), and a carriage frame which moves along the shaft. The carriage frame is driven by a DC servo motor mounted on the carriage frame. Items included in the spacing mechanism are[...]

Page: 51 Service Guide ML520/521 Chapter 2 Principles of Operation Spacing Operation The carriage frame, which contains the printhead and space motor, moves along the carriage shaft parallel to the platen. When the space motor rotates, the driving force is transmitted to the motor gear. As the motor gear rotates, the carriage moves along the platen[...]

Page: 52 Service Guide ML520/521 Chapter 2 Principles of Operation 2.2.03 Head Gap Mechanism The head gap is automatically set for the thickness of the medium loaded in the printer. In the case of envelopes, where the medium thickness varies as the printhead moves along the platen, the strike force of the pins changes to compensate for the differen[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 53 Service Guide ML520/521 Chapter 2 Principles of Operation Ribbon Drive Operation The ribbon drive mechanism feeds the ribbon in synchronization with the spacing operation. The force required to drive the ribbon is obtained from the space motor. The ribbon drive mechanism is composed of the items listed below. Ribbon Drive Gear Assembly Rib[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 54 Service Guide ML520/521 Chapter 2 Principles of Operation 2.2.05 Line Feed Mechanism The line feed operation is accomplished by activating the line feed motor which turns the platen. The rotation of the platen is used to feed paper from the selected paper path. The components of the paper feed mechanism are listed below. Line Feed Motor (p[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 55 Service Guide ML520/521 Chapter 2 Principles of Operation Cut Sheet/Continuous Sheet Switching Mechanism Top Feed (for cut sheet paper) When cut sheet paper is used during normal operation or by the Cut Sheet Feeder (CSF) option, place the change lever in the Top Feed position. As the platen turns, the platen gear causes the idle gear to r[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 56 Service Guide ML520/521 Chapter 2 Principles of Operation Cut Sheet Paper Feed Operation As the line feed motor rotates, power is transferred through the decelerating gears (line feed idler gear, platen gear) to the platen. When using cut sheet paper, the change lever must be in the TOP position so the platen and pressure rollers can feed [...]

Page: 57 Service Guide ML520/521 Chapter 2 Principles of Operation Continuous Paper Feed (Rear Tractor Mechanism) As the platen rotates, power is transferred to the tractor gear from the platen gear, the idler gear, and the change gear. The tractor gear drives the pin tractor belts, which feed the continuous paper. Copyright 1997, Okidata, Division[...]

Page: 58 Service Guide ML520/521 Chapter 2 Principles of Operation Continuous Paper Feed (Pull Tractor Mechanism) Bottom feed of continuous sheets is possible only when an optional pull tractor unit is installed. As the platen rotates, power is transferred to the drive gear from the line feed idler gear, the platen gear, idler gear B and idler gear[...]

Page: 59 Service Guide ML520/521 Chapter 2 Principles of Operation Continuous Paper Feed (Bottom Tractor Feed Mechanism) As the platen rotates, power is transferred to the drive gear from the platen gear, the idle gear and the tractor change gear. The drive gear turns the pin tractor belts on the bottom tractor feed unit, which feeds the continuous[...]

Page: 60 Service Guide ML520/521 Chapter 2 Principles of Operation Continuous Paper Feed (Push/Pull Tractor Mechanism) This mechanism consists of an optional pull tractor and a standard push tractor mechanism. Continuous paper is fed by these two tractors at the same time. Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. [...]

Page: 61 Service Guide ML520/521 Chapter 2 Principles of Operation 2.2.06 Paper Detection Mechanism Top Feed Paper Detection When cut sheet paper is inserted into the printer, Point A of the Rear/Top Paper Feed Lever is pushed backward, causing the Sensor Lever to rotate. As the Sensor Lever rotates, it contacts the Rear Sensor Lever. This makes th[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 62 Service Guide ML520/521 Chapter 2 Principles of Operation 2.2.07 Support Protector Mechanism During printer initialization, the support protector is latched in the stored position (approximately 5 mm from the left bracket of the main frame). Just before paper is loaded, the printhead moves towards the left bracket and unlatches the support[...]

Page: 63 Service Guide ML520/521 Chapter 2 Principles of Operation 2.2.08 Automatic Paper Load The Microline 520/521 printers will automatically detect cut sheet paper and feed the paper to the Top of Form (TOF) position. Cut Sheet Paper Set the change lever to the TOP FEED position. NOTE: When the change lever is in the TOP FEED position, the cut [...]

Page: 64 Service Guide ML520/521 Chapter 2 Principles of Operation Continuous Feed Paper Set the change lever to either the REAR FEED or BOTTOM FEED position. NOTE: When the change lever is in the REAR FEED or BOTTOM FEED position, the cut sheet detection lever does NOT contact the cut sheet detection switch (BASW), which is located on the main con[...]

Page: 65 Service Guide ML520/521 Chapter 2 Principles of Operation 2.2.09 Paper Park If continuous feed paper is installed and printing on cut sheet paper is desired, it is not necessary to unload the continuous feed paper. The Paper Park feature provides a means of retracting the continuous feed paper from the paper path, while (at the same time) [...]

Page: 66 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.1.01 General Information This section lists the parts replacement, adjustment, cleaning, lubrication, and shipping procedures. Disassembly should not be performed unless absolutely necessary. NEVER perform disassembly on a malfunctioning printer until you have followed the f[...]

Page: 67 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.1.02 Maintenance Tools The following tools are required to service the printer. #2 Phillips Screwdriver (with magnetic tip) Straight-slot Screwdriver Needle Nose Pliers (4 Inch) Wire Cutters Digital Multimeter Feeler Gauge (capable of measuring .014 inches) Shop Vacuum Clean[...]

Page: 68 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.1.03 Maintenance Precautions 1. Do not disassemble the unit if it is operating normally. 2. Before starting disassembly and assembly, always turn the AC power switch OFF and pull out the AC plug. 3. Detach the interface cable, if installed. 4. Do not remove parts unnecessari[...]

Page: 69 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2 DISASSEMBLY/ASSEMBLY PROCEDURES General Information This section contains the printer disassembly procedures. Only the removal procedures are explained here. Reverse the procedure for the installation. At the bottom of each procedure is a listing of the parts covered in th[...]

Page: 70 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.01 Preliminary Items 1. Press the AC switch (1) and power off the printer. 2. Remove the paper, if installed (2). 3. Detach the AC power cord (3). 4. Detach the interface cable, if installed (4). P/N 56609701 Cord: AC RSPL Both B.2.03 P/N 56624101 Cord: AC 220V (ML Series)[...]

Partner Exchange (BPX) for any updates to this material. ( http://bpx.okidata.com)[...]

Page: 71 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.02 Printhead Assembly 1. Perform this procedure: 3.2.01. 2. Open the access cover (1). 3. Lift and remove the ribbon. ( Not shown ) 4. Pull the head clamp (2) towards the right and then rotate it up to release the printhead (3). 5. Pull the printhead straight up to remove [...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 72 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.03 Ribbon Protector CAUTION You MUST use a straight slot screwdriver to release the ribbon protector. If you attempt to lift the protector without releasing the tabs, the protector will break. 1. Perform these procedures: 3.2.01 , and 3.2.02 . 2. Open the pull-up roller co[...]

Page: 73 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.04 Gear Case Assembly 1. Perform these procedures: 3.2.01 , and 3.2.02 . 2. Use a straight-slot screwdriver to release the four claws (1) of the gear case assembly (2). 3. Lift and remove the gear case assembly. NOTE: Lubrication --- When lubricating, refer to Section 3.5 [...]

Page: 74 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.05 Pull-up Roller Assembly 1. Perform this procedure: 3.2.01. 2. Open the access cover (1). 3. Open the cover of the pull-up roller assembly (2). 4. Press at A while rotating the assembly towards the back of the printer. 5. Remove the assembly. NOTE: Lubrication When lubri[...]

Page: 75 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.06 Upper Cover, Access Cover, and Sheet Guide Assemblies 1. Perform this procedure: 3.2.01. 2. Pull the platen knob (1) straight out and remove it. 3. Set the change lever (2) to the bottom feed position (toward the rear of the printer). 4. Insert a flat-blade screwdriver [...]

P/N 51009401 Guide: Sheet (Narrow) RSPL 520 B.2.02 P/N 51009501 Guide: Sheet (Wide) RSPL 521 B.2.02 P/N 53066902 Cover: Upper (Narrow) RSPL 520 B.2.02 P/N 53067002 Cover: Upper (Wide) RSPL 521 B.2.02 P/N 53067101 Cover: Access (Narrow) RSPL 520 B.2.02 P/N 53067201 Cover: Access (Wide) RSPL 521 B.2.02 P/N 53067301 Cover: (B) for card slot RSPL Both [...]

Page: 76 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.07 Control Board (FJIM) 1. Perform these procedures: 3.2.01 , and 3.2.06 . 2. Remove the two screws (1). 3. Release the control board (2) from the bracket (3). 4. Tilt the board to access the connectors. 5. Detach connectors CN6 - operator panel (4), CN7- carriage cable (5[...]

P/N 55072401 PCB: FJIM (w/o ROM) RSPL Both B.2.03 P/N 55938301 IC: EEPROM BR93CC46A RSPL Both B.2.03 Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 77 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.08 Power Supply Assembly 1. Perform these procedures: 3.2.01 and 3.2.06 . 2. Use a straight slot screwdriver to detach the claws from both sides of the cable clamp (1). 3. Remove the cable clamp (2). 4. Detach the transformer cable from connector CN3 (3) of the control boa[...]

P/N 56412401 Transformer: 120 V ML520 RSPL 520 B.2.03 P/N 56412402 Transformer: 120 V ML521 RSPL 521 B.2.03 P/N 55073201 PCB: Filter 120 V RSPL Both B.2.03 P/N 50707501 Clamp: Cord RSPL Both B.2.03 P/N 56306201 Fuse: 1A 250V (Filter Brd 220V) Option RSPL Both B.2.03 P/N 56306101 Fuse: 2.5A 125V (Filter Board) RSPL Both B.2.03 Copyright 1997, Okidat[...]

Page: 78 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.09 Operator Panel PCB (LEOP) 1. Perform these procedures: 3.2.01 , 3.2.06 , and 3.2.07 . 2. Cut the nylon tie and release the cable. (Not shown) 3. Disengage the claws (1) on both sides of the frame. 4. Lift the operator panel assembly (2) straight up and remove it. 5. Ope[...]

Page: 79 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.10 PC Connector 1. Perform these procedures : 3.2.01 , 3.2.02 , and 3.2.04 . 2. Remove the two screws (1) and the connector holders. The holders are not shown. 3. Remove the PC connector (2). NOTE: Installation Do not touch the contacts of the PC connector. Do not touch th[...]

P/N 56729601 Connector: PC HD40 RSPL Both B.2.07 Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 80 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.11 Space Motor and Roller Guide Assemblies 1. Perform these procedures: 3.2.01 , 3.2.02 , 3.2.04 , and 3.2.10 . 2. Remove the three screws (1). 3. Lift the space motor assembly (2). 4. Remove the left (3) and right connector holders (4). 5. Remove the roller guide assembly[...]

P/N 53343001 Holder: Connector (L) RSPL Both B.2.07 P/N 53343101 Holder: Connector (R) RSPL Both B.2.07 P/N 56510401 Motor: Space Assembly RSPL Both B.2.07 P/N 53343301 Guide: Roller Assembly Both B.2.07 P/N 53341901 Roller: Guide RSPL Both B.2.07 P/N 53342001 Holder: Guide Roller RSPL Both B.2.07 P/N N/A Pin Both B.2.07 P/N N/A Guide Roller Spring[...]

Page: 81 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.12 Carriage Cable 1. Perform these procedures: 3.2.01 , 3.2.06 , 3.2.07 , and 3.2.11 . 2. Slightly bow the carriage cable (1) to release it from the claws (2) and the projection on the main frame (3). 3. Remove the carriage cable guide (4). 4. Remove the carriage cable. NO[...]

Page: 82 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.13 Space Rack 1. Perform these procedures: 3.2.01 , 3.2.02 , 3.2.04 , 3.2.10 , and 3.2.11 . 2. Remove the spring (1). 3. Disengage the claws (2) on the both ends of the space rack (3). 4. Pull the space rack straight up and remove it. NOTE: Installation After installing th[...]

P/N 50923501 Spring: Tension (Space Rack) RSPL Both B.2.04 P/N 53563301 Rack: Space (Narrow) RSPL 520 B.2.04 P/N 53563401 Rack: Space (Wide) RSPL 521 B.2.04 Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 83 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.14 Roller/Holder Backup Assembly 1. Perform these procedures: 3.2.01 , 3.2.02 , 3.2.04 , 3.2.10 , and 3.2.11 . 2. Use a small straight slot screwdriver to disengage the claws of the backup roller holder spring (1) from the carriage frame (2). 3. Remove the roller/holder ba[...]

Page: 84 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.15 Guide Rail and Adjust Cam 1. Perform these procedures: 3.2.01 , 3.2.02 , 3.2.04 , 3.2.10 , 3.2.11 , and 3.2.14 . 2. Rotate the adjust cam (1) in the direction of arrow A as far as possible. 3. Pull the cam out and remove it. 4. Carefully press the claw (2 location only [...]

P/N 51009801 Guide: Rail (Narrow) RSPL 520 B.2.04 P/N 51009901 Guide: Rail (Wide) RSPL 521 B.2.04 P/N 53067701 Cam: Adjust RSPL Both B.2.04 Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 85 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.16 Left Ground Plate 1. Perform these procedures: 3.2.01 , 3.2.06 , and 3.2.07 . 2. Cut the nylon tie and release the cable. (Not shown). 3. Work the left ground plate (1) up, and then out, to remove it. P/N 51010301 Plate: Left Ground RSPL Both B.2.04 Copyright 1997, Okid[...]

Page: 86 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.17 Right Ground Plate 1. Perform these procedures: 3.2.01 , and 3.2.06 . 2. Pull the top tabs (1) of the right ground plate (2) out to free the plate from the claws of the base frame. You may have to use a screwdriver to work the plate tabs free. 3. Lift the plate and remo[...]

Page: 87 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.18 Rear and Cut Sheet Paper Feed Sensor Levers 1. Perform these procedures: 3.2.01 , 3.2.06 , 3.2.07 , 3.2.16 , and 3.2.20 . 2. Turn the cut sheet/continuous feed paper sensor lever (1) until the flag is at the top, then work the lever free. 3. Remove the lever. 4. Turn th[...]

Page: 88 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.19 Platen Assembly 1. Perform these procedures: 3.2.01 , and 3.2.06 . 2. Move the change lever (1) to the bottom feed position (to the rear of the printer). 3. Push the lock levers (2) in, then rotate them towards the front to unlock them from the frame. 4. The levers shou[...]

P/N 50098301 Platen Assembly (Narrow) RSPL 520 B.2.05 P/N 50098302 Platen Assembly (Wide) RSPL 521 B.2.05 Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 89 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.20 Paper Chute Assembly 1. Perform these procedures: 3.2.01 , 3.2.06 , and 3.2.19 . 2. Remove the rear pressure roller (1). 3. Use a straight slot screwdriver to release the claws of the lock spring (2) and remove the spring. 4. Remove the paper chute assembly (3). NOTE: T[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. ( http://bpx.okidata.com)[...]

Page: 90 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.21 Line Feed Motor Assembly 1. Perform these procedures: 3.2.01 , 3.2.06 , 3.2.07 , 3.2.16 , 3.2.19 , 3.2.20 , and 3.2.21 (this section). 2. Firmly press down on the line feed motor assembly (1) while tilting the assembly out. 3. Remove the line feed motor assembly. 4. Rem[...]

P/N 56627201 Cord: Connection Line Feed RSPL Both B.2.04 Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 91 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.22 Reset Spring CAUTION: Please read through this entire procedure before performing it. Do not press against the vertical extensions of the reset spring at any time during this procedure. Firm pressure will release the spring, not brute force. 1. Perform these procedures:[...]

Page: 92 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.23 Idle Gear and Change Lever 1. Perform these procedures: 3.2.01 , 3.2.06 , 3.2.07 , 3.2.16 , 3.2.17 , 3.2.19 , 3.2.20 , and 3.2.22 . 2. Remove the idle gear (1). The idle gear is a large narrow gear. 3. Release the claw (2) of the change lever (3). The claw is accessed f[...]

P/N 50805101 Lever: Change RSPL Both B.2.05 P/N 51228201 Gear: Idle RSPL Both B.2.05 Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 93 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.24 Pressure Spring 1. Perform these procedures: 3.2.01 , 3.2.06 , 3.2.07 , 3.2.16 , 3.2.17 , 3.2.19 , 3.2.20 , 3.2.22, and 3.2.23 . 2. Turn the front release gear arm (1) until it is disengaged. 3. Remove the release cam (2). This is the medium size, thick cam. 4. Work the[...]

P/N 50805201 Lever: Switch RSPL Both B.2.06 P/N 50805301 Cam: Release RSPL Both B.2.05 P/N 50923301 Spring: Pressure (Narrow) RSPL 520 B.2.06 P/N 50923401 Spring: Pressure (Wide) RSPL 521 B.2.06 P/N 51228301 Arm: Front Release Gear RSPL Both B.2.06 Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business [...]

Page: 94 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.25 Carriage Shaft CAUTION The space motor assembly, etc. may be left in place when removing the carriage shaft. However, use extra care when doing so. The carriage cable should be detached from the space motor before removing the carriage shaft. 1. Perform these procedures[...]

P/N 50098901 Carriage: Frame Set RSPL Both B.2.07 P/N 50923601 Spring: Support Protect Reset RSPL Both B.2.04 P/N 53067601 Protector: Support (Assembly) RSPL Both B.2.04 P/N 53563501 Shaft: Carriage (Narrow) RSPL 520 B.2.04 P/N 53563502 Shaft: Carriage (Wide) RSPL 521 B.2.04 Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved[...]

Page: 95 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.26 Leaf Spring 1. Perform these procedures: 3.2.01 , 3.2.06 , 3.2.07 , 3.2.16 , and 3.2.25 . 2. Position the unit so you can access the top and bottom of the leaf spring (1). 3. Start at one end of the spring. 4. Use a straight slot screwdriver to release the bottom extens[...]

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Page: 96 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.27 Bottom Paper Sensor Levers 1. Perform these procedures: 3.2.01 , 3.2.06 , 3.2.07 , 3.2.16 , 3.2.17 , 3.2.19 , 3.2.20 , 3.2.22 , 3.2.23 , and 3.2.24 . 2. Working from the underside of the unit, release the claws of the paper pan (1). When you release a claw, push on the [...]

P/N 50804701 Lever: Bottom Sensor RSPL Both B.2.04 P/N 51227801 Shaft: Front Release Gear RSPL 520 B.2.06 (Narrow) P/N 51227901 Shaft: Front Release Gear (Wide) RSPL 521 B.2.06 Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.oki[...]

Page: 97 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.28 Front Pressure Roller Assembly 1. Perform these procedures: 3.2.01 , 3.2.06 , 3.2.07 , 3.2.16 , 3.2.17 , 3.2.19 , 3.2.20 , 3.2.22 , 3.2.23 , and 3.2.24 , 3.2.27 . 2. Separate the arms of the front roller holders (1) and remove the front pressure roller (2). 3. Squeeze t[...]

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Page: 98 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.29 Tractor Assembly 1. Perform these procedures: 3.2.01 , 3.2.06 , 3.2.07 , 3.2.16 , 3.2.17 , 3.2.19 , 3.2.20 , 3.2.22 , 3.2.23 , and 3.2.24 . 2. Use a needle nose pliers to release the claw of the tractor gear (1) and remove the gear. 3. Remove the change gear (2). 4. Rai[...]

P/N 50097501 Tractor: Assembly (Narrow) RSPL 520 B.2.06 P/N 50097502 Tractor: Assembly (Wide) RSPL 521 B.2.06 P/N 51228001 Gear: Change RSPL Both B.2.05 P/N 51228101 Gear: Tractor RSPL Both B.2.05[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. ( http://bpx.okidata.com)[...]

Page: 99 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.2.30 Main Frame 1. All disassembly procedures must be carried out to reach the base frame (1). P/N 53563101 Frame: Main (Narrow) RSPL 520 B.2.04/5/6 P/N 53563201 Frame: Main (Wide) RSPL 521 B.2.04/5/6 Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved[...]

Page: 100 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.3 PRINTER ADJUSTMENTS 3.3.01 General Information This section contains the procedures for performing adjustments on the printer. These procedures may be required when replacing either consumables or parts. The disassembly/assembly procedures list the required adjustments an[...]

Page: 101 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.3.02 Printhead Gap Adjustment General Information Before performing this adjustment, always verify that the printhead is properly installed. This adjustment should be performed when the following parts are replaced. 1. Printhead (3.2.02) 2. Space Motor Assembly (3.2.11) 3. [...]

1. Remove the upper cover and pull roller assembly. 2. Move the change lever to the rear paper feed position. 3. Rotate the platen. 4. Set the gap change gear (Figure 1 A) to Range 2 by turning the adjust screw using a small phillips screwdriver. Turn this screw slowly while moving the carriage (1) to the left (if turning the screw counter clockwis[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 102 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.3.03 Key Combinations Key Combinations Description SEL + LF (Hold during Power-ON) Reset Menu to Factory Defaults. SEL (Hold during Power-ON) Access Menu (if Menu set to LIMITED OPERATION) QUIET + FF/LOAD (Hold during Power-ON) Reset Top of Form to Factory Default (1 inch) [...]

Page: 103 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.3.04 Menu Operation General Information The menu is used to customize the printers settings and features. The Menu is made up of a number of Groups. Each Group has a list of Items. Each Item has several Settings. Menu Mode To place the printer in the Menu Mode, follow this [...]

could damage / destroy the printhead, platen, and ribbon. 4. Press and hold the SHIFT switch while pressing the SEL switch. 5. The MENU lamp will light. If the printer was selected, the SELECT lamp will light. When in Menu Mode, the functions printed below the operator panel switches are active. 6. Press the PRINT switch. 7. The Menu will print. 8.[...]

To access the menu when the printer is set to Limited Operation, follow this procedure. 1. Verify that continuous feed paper is installed. 2. Verify that the ribbon is correctly installed. 3. Verify that the width of the installed paper matches the paper width menu setting. CAUTION: If the Menu is set for wide paper, and narrow paper is used, the p[...]

Page: 104 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly Menu Settings Factory default settings are printed in Bold Italic . The tables show all possible menu settings available with the Microline 520/521. What you will actually see depends on the active emulation and the options installed. Group Item Setting Printer Control Emulat[...]

Page Width * 13.6" 8" Page Length 11 11 2/3 12 14 17 3 3.5 4 5.5 6 7 8 8.5 " Gap Control Auto Gap Semi Auto Gap 1 2 3 4 5 6 7 8 9 Bottom Feed Line Spacing 6 8 LPI Form Tear-Off Off 500 ms 1 sec 2 sec Skip Over Perforation No Yes Page Width * 13.6" 8" Page Length 11 11 2/3 12 14 17 3 3.5 4 5.5 6 7 8 8.5 " Gap Control Au[...]

Paper Out Override No Yes Print Registration O 0.05 mm Left 0.10 mm Left 0.15 mm Left 0.20 mm Left 0.25 mm Left 0.25 mm Right 0.20 mm Right 0.15 mm Right 0.10 mm Right 0.05 mm Right Operator Panel Function Full Operation Limited Operation Reset Inhibit No Yes Print Suppress Effective Yes No Auto LF No Yes Auto CR * * * * No Yes CSF Bin Select * * *[...]

The tables show all possible menu settings available with the Microline 520/521. What you will actually see depends on the active emulation and the options installed. Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 105 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.3.05 Top of Form General Information Top of Form is the distance from the top edge of the paper to the first print position on the page. The red line on the ribbon protector indicates the baseline of the Top of Form. Setting Top of Form 1. Deselect the printer. The SEL lamp[...]

Page: 106 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.3.06 Paper Park General Information Paper Park allows the user to print using single (cut) sheet pages without removing continuous forms from the printer. Procedure: Continuous Feed to Single Sheet 1. Remove any printed pages from the printer. 2. Press PARK to retract the c[...]

Page: 107 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.3.07 Tear Feature NOTE: Tear is activated by pressing TEAR. It is a manual procedure. FORMS TEAR OFF is activated by changing a setting in the Menu. It is an automatic procedure. General Information This feature allows a printed page (rear or bottom feed, continuous form) t[...]

Page: 108 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.3.08 Forms Tear Off NOTE: Tear is activated by pressing TEAR. It is a manual procedure. FORMS TEAR OFF is activated by changing a setting in the Menu. It is an automatic procedure. General Information This feature allows a printed page (rear or bottom feed, continuous form)[...]

Press Micro Feed Up to advance the paper. Press Micro Feed Down to retract the paper. 6. Enter Menu Mode. 7. Enable Form Tear Off. 8. Exit Menu Mode. Setting 1. Verify that continuous feed paper is installed. 2. Verify that the ribbon is correctly installed. 3. Verify that the width of the installed paper matches the paper width menu setting. 4. Po[...]

Page: 109 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.3.09 Resets Reset Menu to Factory Defaults CAUTION: Once the menu has been reset, all customized menu settings will be lost. Always print the menu before resetting the printer to factory defaults. To reset the menu to factory default settings, follow this procedure. 1. Befo[...]

Page: 110 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.4 CLEANING 3.4.01 General Information An accumulation of paper dust is the most frequent cause of print quality problems in a dot matrix printer. Small pieces of paper can cause paper jams. A dirty platen will smudge paper. It is important to clean the printer regularly, pa[...]

Page: 111 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.5 LUBRICATION 3.5.01 General Information If the lubrication procedures are not performed properly, the printer will require more frequent cleaning. Excessive lubricant attracts dust and accumulations build up quickly. An accumulation of paper dust is the most frequent cause[...]

3.5.06 Areas Not Lubricated Lubricant should never contact the parts listed below. 1. Ribbon 2. Platen Assembly (Rubber Face) 3. Pressure Roller (Rubber Face) 4. Tractor Pins 5. Head Cable 6. Space Motor Printed Circuit Board 7. Electrical Contacts and Connections 8. Space Rack CAUTION Do NOT lubricate the space rack. Lubricating the space rack wil[...]

Page: 112 Service Guide ML520/521 Chapter 3 Maintenance & Disassembly 3.6 SHIPPING INSTRUCTIONS 3.6.01 Return for Service CAUTION: When shipping the printer, use the original packaging to prevent damage. Be sure to secure the printhead so it will not move during shipment. 1. Locate the original packaging or order replacement packaging from Okid[...]

Page: 113 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.1.01 Introduction This section is used to isolate problems to the assembly level. Application problems and detection of faulty components on the printed circuit boards are NOT addressed. When troubleshooting a defective unit, follow these steps. 1. Refer to Section 4.3, whi[...]

Page: 114 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.1.02 Printer Serial Number Identification To identify the revision level of a printer, record the serial number from the back of the printer. Refer to the following to decode the serial number. Example Printer Serial Number: 401A0154693 Date Code 401 (4 = year. 01 = month) [...]

Page: 115 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.1.03 Firmware Revision Identification To identify the revision level and part number of the firmware, print the Rolling ASCII Test or the Font Test. Refer to Section 4.8 of this Service Handbook for information on printing the tests. Header At the top of the test is a heade[...]

Page: 116 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.2 REPORTING PROBLEMS - General Information 4.2.01 General Information Okidata strives to provide accurate and detailed service information through its training materials. The Technical Training Group realizes that service technicians have valuable experience, knowledge, and[...]

Page: 117 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.2.02 Problem Lists Technicians frequently request a list of common problems specific to a product. Technical Training Kits are written before a product is shipped to customers. Therefore, such information is NOT available when a product is first released. However, Okidata w[...]

Page: 118 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.2.03 Reporting Methods Okilink II You may use Okilink II to report your findings. Refer to the Service Center Reference Guide for information on using Okilink II. Course Critique Use the Course Critique to report any problems you find as you are completing the self-paced tr[...]

Page: 119 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.3 TROUBLESHOOTING UPDATES 4.3.01 General Information Okidata distributes updated troubleshooting information in three ways. Okilink II Faxable Facts Technical Service Bulletins 4.3.02 Okilink II Okilink II is Okidata's Bulletin Board Service. This service is available [...]

Page: 120 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.4 TROUBLESHOOTING TIPS 4.4.01 Preliminary Checks 1. Is the product being operated under the proper ambient conditions? 2. Does the paper being used meet the specifications for this product? 3. Has the ribbon been replaced as recommended? 4. Has the ribbon been installed pro[...]

Page: 121 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.4.02 Problem Categories There are three categories of problems that you might encounter when servicing the printer. ALARM Lamp Blinks (Fatal Errors) The following can cause the ALARM lamp to blink. Open Bail Arm Jammed Paper Printhead Cannot Move Other Fatal Error When the [...]

Page: 122 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.4.03 START HERE Flowchart START Power ON the unit. Does the printer initialize? No Is the ALARM Lamp Blinking? No Refer to RAP 01. Yes Refer to Section 4.6 of the Service Handbook. Yes Load the printer with paper. Does the paper load without jamming? No Refer to RAP 04. Yes[...]

Page: 123 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.4.04 Tips for Preventing Image Problems 1. Make sure that the ribbon is not "dried out". If the printer output is faded, install a new ribbon, then print another sample. 2. Make sure that the paper you are using is within specifications. Paper specifications can b[...]

Page: 124 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.4.05 Common Problems 1. Nothing happens when the unit is powered on. The unit may not be plugged in. Check the power cord connection to the outlet and to the printer. If a power strip is being used, make sure that it is powered ON. Check to be sure that an external fuse has[...]

Handbook, the more compatible it will be with your printer. If your software does not have any of the indicated drivers available, check with the software manufacturer to see if they have added any additional drivers since you purchased your software. If you have embedded any printer commands in your software, check to be sure that you have entered[...]

the initialization string may still override the printer MENU and / or front panel settings. The I-Prime signal is sent over the parallel interface (pin 31) and will automatically override any settings you have made using the front panel buttons. To eliminate this problem, enter the Menu Mode (hold down the SHIFT button while pressing SEL/MENU butt[...]

Page: 125 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.5 ABNORMAL OUTPUT - Output Samples 4.5.01 Output Samples Light Print on the Entire Page Possible Causes: 1. Ribbon is "dried out". Replace the ribbon. 2. Verify that the headgap menu setting is appropriate for the type of paper being used. 3. Check / perform the p[...]

2. Defective platen. Replace the platen. Smeared Print Possible Causes: 1. Ribbon protector is missing or broken. Replace the ribbon protector. 2. Verify that the headgap menu setting is appropriate for the type of paper being used. 3. Check / perform the printhead gap adjustment. 4. Paper is not within specification. Refer to Section One for paper[...]

Drifting Margin Possible Causes: 1. Power OFF the printer. Move the carriage assembly. The carriage should move smoothly. If it does not, remove the cause of the binding. 2. Refer to the next section and / or Technical Service Bulletin 3309. Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner[...]

Page: 126 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis Left Margin Drifting Problem NOTE: This information is also provided in Technical Service Bulletin 1707. To correct a problem with the left margin drifting during print operations, follow this procedure. 1. Manually slide the carriage assembly back and forth along the full le[...]

Page: 127 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.6 FAULT ALARMS 4.6.01 General Information Follow these guidelines when using the Troubleshooting Tables. CAUTION: Always check that all connectors on the printer are making good contact. 1. Record the status (OFF, solidly ON, Blinking) of the Operator Panel LEDs. 2. Go to t[...]

Page: 128 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.6.02 ALARM/LED Display Troubleshooting Table Index CAUTION: Always check that all connectors on the printer are making good contact. NOTE: Reference Numbers 25 and 26 use identical Operator Panel displays ALAR M UTILITY PRO P NLQ HSD 10 12 15 17 20 SE L MENU Referen ce Numb[...]

Blinkin g On 12 Blinkin g On On 13 Blinkin g On On 14 Blinkin g On 15 Blinkin g On On 16 Blinkin g On On 17 Blinkin g On On 18 Blinkin g On On 19 Blinkin g On On 20 Blinkin g On On 21 On On On On On 22 On Blin kin g On 23 On Blin kin g On 24 On On On Blinkin g 25 On On On Blinkin g 26 Copyright 1997, Okidata, Division of OKI America, Inc. All right[...]

Page: 129 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.6.03 ALARM/LED Display Troubleshooting Tables CAUTION: Always check that all connectors on the printer are making good contact. Reference Number Failure Description Cause Recommended Action 1 Space Motor Alarm Space motor IPT does not occur in specified time. Refer to RAP 0[...]

8 Printhead Connection Alarm (2) Self adjust was not successful. Head gap is too small or too narrow. Check the printhead connection. Then replace the main control board the carriage cable and the printhead. 9 Line Feed / Space Motor Driver Alarm High driver temperature. The TSD signal has not changed. Replace the following: main control board line[...]

Page: 130 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.7 REPAIR ANALYSIS PROCEDURES (RAPs) 4.7.01 Using the RAPs When using the Repair Analysis Procedures, follow these steps. 1. Go to the RAP Index. 2. Find the RAP which is associated with the printers problem. 3. Go to the appropriate RAP. 4. All RAPs begin with a START state[...]

Page: 131 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.7.02 RAP Index RAP Number Description 1 No Power Supplied to Printer 2 No Spacing Operation 3 Printhead Homing Error 4 Paper Jam During Paper Loading 5 Printhead Not Firing Pins 6 Poor Print Quality 7 Ribbon Feed Problem 8 Line Feed Problem 9 Operator Panel Malfunction 10 P[...]

Page: 132 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis RAP 01 No Power Supplied to Printer START The printer does not power On when the AC switch is turned ON. Check the AC cable. Is it correctly connected? Yes Check the fuse on the power supply board and F1 of the main control board. Are they open? No Go to A. Yes Replace the fu[...]

1. Ribbon Feed Mechanism. 2. Carriage Cable. 3. Main Control Board 4. PROM 05CA Has the problem been resolved? Yes End of procedure. No Contact Technical Support. Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 133 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis RAP 02 No Spacing Operation START The alarm LED blinks. Is the carriage assembly binding or jammed? No Make sure the carriage cable is properly connected to the space motor assembly and CN7 on the main control board. Go to A. Yes 1. Remove the ribbon to verify that the ribbon[...]

Has the problem been resolved? Yes End of procedure. No Contact Technical Support. Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 134 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis RAP 03 Printhead Homing Error START Printhead does not return to the home position. Make sure the carriage cable is properly connected to the space motor assembly and CN8 on the main control board. Make sure the power connector cable is properly connected to CN3 on the main c[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 135 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis RAP 04 Paper Jam During Paper Loading START Check paper path release lever for proper position. Make sure the paper path is clear. Which of the following paper jams have occurred? 1. Paper bent at top left corner. Check the support protector to see if it covers the left side [...]

Page: 136 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis RAP 05 Printhead Pins Not Firing START Missing dots on output. Verify that the printhead gap is set correctly. Ensure the carriage cable is making firm contact with CN7 on the main control board and the space motor assembly. Inspect both ends of the carriage cable for worn ed[...]

Page: 137 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis RAP 06 Poor Print Quality START Is the print head gap properly set? Yes Go to A No Go to B A Replace the printhead Has the problem been resolved? Yes End of procedure. No Go to C. C Replace the main control board. Has the problem been resolved? Yes End of procedure. No Check [...]

Page: 138 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis RAP 07 Ribbon Feed Problem START The ribbon feed does not function properly. Verify that both ends of the carriage cable are connected correctly. Make sure the ribbon shield is fastened properly. Remove the ribbon cartridge. Grasp the carriage. Manually move the carriage left[...]

Page: 139 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis RAP 08 Line Feed Problem START No line feed operation. Make sure that the line feed cable is properly connected to the line feed motor and CN5 of the main control board. Power OFF the printer. Manually rotate the platen. Does the platen rotate smoothly? Yes Go to A No Is the [...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 140 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis RAP 09 Operation Panel Malfunction START The operation panel does not function properly. Do the operation panel LEDs light when power is applied? Yes Make sure the cable from CN1 of the operation panel is properly connected to CN7 on the main control board. Go to A No Check t[...]

Page: 141 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis RAP 10 Parallel Interface Problem START No parallel port communication. Is the SEL LED blinking? Yes The printer is in the Print Suppress mode. Disable the menu item Print Suppress if the function is not required. End of procedure. No Does the SEL LED light ? Yes Go to A No P[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 142 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis RAP 11 Serial Interface Problem START. Are you using a cable with the proper number of pins? No Change the interface cable. Has the problem been resolved? Yes End of procedure No Go to A Yes Is the ALARM LED blinking? Yes Refer to Section 4.6 of the Service Handbook. Has the [...]

No Replace the RS232C board. Are + 8 vdc / - 8 vdc present on the main control board? (Refer to Appendix A of this Service Handbook). Yes Replace the RS232C board. Has the problem been resolved? Yes End of procedure. No Contact Technical Support. No Replace the main control board. Has the problem been resolved? Yes End of procedure. No Contact Tech[...]

Page: 143 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.8 PRINTER TESTS 4.8.01 General Information This section covers the tests listed below. Rolling ASCII Test Font Test Serial Interface Loopback Test Hexadecimal Dump Mode The Rolling ASCII and Font Tests check print operations. The Serial Interface Loopback Test checks the op[...]

Page: 144 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.8.02 Rolling ASCII Test General Information The rolling ASCII test is a continuous printout of all 96 ASCII characters. Use this test to check the following items. 1. Print Quality Across the entire length of a line Down the entire page 2. Line Spacing 3. Left Margin Alignm[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 145 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.8.03 Font Test General Information The font test is a one page sample printout of each available typeface. HSD 10 cpi HSD 12 cpi HSD 17.1 cpi Utility 10 cpi Utility 12 cpi Utility 17.1 cpi NLQ 10 cpi NLQ 12 cpi NLQ 10 cpi Double Height / Double Width At the top of the test [...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 146 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.8.04 Serial Interface Loopback Test NOTE: In order to run this test, the serial interface board must be installed with a serial loopback test connector attached to it. To perform the serial interface loopback test, follow these steps. 1. Place the printer in the Serial Diag[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 147 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis Serial Cable Information The information in this section will help you make a serial cable to connect between the printer and computer. Refer to the computer documentation to determine the cable requirements on the computers end. The printer has the following cable requiremen[...]

Page: 148 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis Serial Interface Signal Requirements Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 149 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis Commonly Used Serial Cable Configurations IBM 25-Pin Cable Configuration Computer Printer IBM 9-Pin Cable Configuration Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material[...]

Page: 150 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.8.05 Hexadecimal Dump Mode General Information The hexadecimal dump mode allows you to view the data sent from a computer to the printer. When the printer is in hex dump mode, all data received (both printable characters and control codes) will be printed in both hexadecima[...]

Page: 151 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.9 RESISTANCE CHECKS 4.9.01 General Description The charts on the following pages provide information needed to determine if the printhead and motors used in the printer are defective. NOTE: The printhead coil resistance values ARE NOT LISTED. The individual printwire contro[...]

Page: 152 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis Layout Diagram Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 153 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.9.02 Printhead Interconnect Diagram: Control Board to Printhead NOTE: The printhead coil resistance values ARE NOT LISTED. The individual printwire control lines CANNOT be accessed on this printhead. Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved[...]

Page: 154 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.9.03 Line Feed Motor Resistance The resistance of each coil should be approximately 13 ohms. Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com[...]

Page: 155 Service Guide ML520/521 Chapter 4 Failure & Repair Analysis 4.9.04 Space Motor Resistance The resistance of each coil should be approximately 5 ohms. Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 156 Service Guide ML520/521 Chapter A Reference Charts A.1 OVERVIEW - A.1.01 General Information This section describes the characteristics of the printed circuit boards used in the unit. The following areas are covered. Function Firmware Fuses Jumpers Sensors Switches Test Points Where an item is not applicable, the word NONE will be listed.[...]

Page: 157 Service Guide ML520/521 Chapter A Reference Charts A.2 INDEX TO CHARTS Description Board Designation Section Main Controller Board FJIM A.2.01 Operator Panel Board LEOP A.2.02 Power Supply Assembly N/A A.2.03 Space Motor Board N/A A.2.04 RS232-C Serial Interface Board LXHI A.2.05 Copyright 1997, Okidata, Division of OKI America, Inc. All [...]

Page: 158 Service Guide ML520/521 Chapter A Reference Charts Board Layout Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 159 Service Guide ML520/521 Chapter A Reference Charts A.2.01 Main Controller Board (FJIM) Function The main controller board contains a microprocessor, EPROM, EEPROM, drive circuitry, 128 Kbyte DRAM, sensors and interface connector. The AC voltages from the power supply are rectified and regulated on the main controller board. Firmware 05CB:[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 160 Service Guide ML520/521 Chapter A Reference Charts A.2.02 Operator Panel Board (LEOP) Function The operator panel control LSI send commands to the microprocessors serial I/O port whenever the operator panels switches are pressed. The operator panel LED display provides information on fault alarms and printer status. Firmware NONE Fuses NO[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. ( http://bpx.okidata.com)[...]

Page: 161 Service Guide ML520/521 Chapter A Reference Charts A.2.03 Power Supply Assembly Function The power supply board is comprised of a noise filter board and transformer. The power supply board provides AC voltages to the main controller board via CN-3. Firmware NONE Fuses F1: 125/250V 2.5 amp. AC line fuse Jumpers NONE Sensors NONE Switches S[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 162 Service Guide ML520/521 Chapter A Reference Charts A.2.04 Space Motor Board Function The space motor board contains an encoder disk and photosensor. The encoder disk and the photosensor generate phase signals. These signals governs the speed and direction of the space motor via the LSI and microprocessor. Firmware NONE Fuses NONE Jumpers [...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 163 Service Guide ML520/521 Chapter A Reference Charts A.2.05 RS232-C Serial Interface Board - Option (LXHI) Function This board provides you serial interface capabilities. The serial interface parameters can be set through the printer menu. Firmware Masked to the MPU: Socket is empty Fuses NONE Jumpers SP1: EPROM Address Select Jumper (posit[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 164 Service Guide ML520/521 Chapter B Illustrated Parts Listing B.1 OVERVIEW - B.1.01 General Information This appendix will assist you in identifying the assemblies and parts of the product. Use Section Four (Failure Analysis) to determine the defective part(s). Locate the part and its part number in this section. Appendix B is cross-referen[...]

Page: 165 Service Guide ML520/521 Chapter B Illustrated Parts Listing Format The format for this appendix is a series of tables with diagrams. The tables contain the item reference number, the Okidata and Oki-Japan (Oki-J) part numbers, the part description, a comments section, and the disassembly procedure. Items with the comments RSPL (Recommende[...]

Page: 166 Service Guide ML520/521 Chapter B Illustrated Parts Listing Current Part Numbers Okidata has made every effort to include current part numbers in this Service Handbook at the time of publishing . However, technical information frequently changes. These changes often include new or modified parts, with new or modified part numbers. Please [...]

Page: 167 Service Guide ML520/521 Chapter B Illustrated Parts Listing B.1.02 Definition of Terms Assemblies Assemblies are parts grouped under a single description and/or part number. Generally, individual items in an assembly are not available from Okidata. Assemblies are surrounded by broken line boxes in the diagrams. Assemblies will say "I[...]

information updates. Okidata distributes the TSBs through Okilink II. The TSBs are issued monthly. 520 This part is specific to the Microline 520 printer. 521 This part is specific to the Microline 521 printer. Both This part is used by both the Microline 520 and Microline 521 printers. Copyright 1997, Okidata, Division of OKI America, Inc. All rig[...]

Page: 168 Service Guide ML520/521 Chapter B Illustrated Parts Listing B.1.03 Parts Ordering Information Service Center Reference Guide When a technician has successfully completed a Service Training Course for a product and the Dealer has become Service Authorized, an information package is provided to the Dealer. The Okidata Service Center Referen[...]

Page: 169 Service Guide ML520/521 Chapter B Illustrated Parts Listing B.2 CHARTS Below is an index to the illustrated parts breakdown charts. Section Description B.2.01 Printer B.2.02 Upper Cover Assembly B.2.03 Printer General Assembly B.2.04 Printer Unit (1 of 3) B.2.05 Printer Unit (2 of 3) B.2.06 Printer Unit (3 of 3) B.2.07 Carriage Assembly B[...]

Page: 170 Service Guide ML520/521 Chapter B Illustrated Parts Listing Overview Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 171 Service Guide ML520/521 Chapter B Illustrated Parts Listing B.2.01 Printer Part numbers are subject to change. Refer to Okilink II for current part numbers and pricing information. Item Okidata P/N Oki-J P/N Description Comments Refer to B.1.02 Disassembly Procedure 1 62409001 N/A Printer: ML520 Parallel (Epson/IBM/ML Comp.) 120 V N/A 2 6[...]

Page: 172 Service Guide ML520/521 Chapter B Illustrated Parts Listing B.2.02 Upper Cover Assembly Item Okidata P/N Oki-J P/N Description Comments Refer to B.1.02 Disassembly Procedure 1 53066902 1PP4094-6501P2 Cover: Upper (Narrow) RSPL 520 3.2.06 1 53067002 1PP4094-7201P2 Cover: Upper (Wide) RSPL 521 3.2.06 2 51009401 N/A Guide: Sheet (Narrow) RSP[...]

3 53067201 2PA4094-7382G1 Cover: Access (Wide) RSPL 521 3.2.06 Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 173 Service Guide ML520/521 Chapter B Illustrated Parts Listing B.2.03 Printer General Assembly Item Okidata P/N Oki-J P/N Description Comments Refer to B.1.02 Disassembly Procedure 1 53562601 2PP4094-6507P3 Knob: Platen (ML500 Series) RSPL Both 3.2.06 2 53067301 2PP4094-6506P1 Cover: (B) for Card Slot RSPL Both 3.2.06 3 55072401 4YA4042-1515[...]

5 55937502 4YA4042-1516G2 PCB: LEOP (Operator. Panel) RSPL Both 3.2.09 6 53562703 3PP4025-3670G3 Panel: Operator RSPL Both 3.2.09 7 56412401 4YB4049-7030P1 Transformer: 120 V ML520 RSPL 520 3.2.08 7 56412402 4YB4049-7030P2 Transformer: 120 V ML521 RSPL 521 3.2.08 8 55073201 4YB4021-1143P1 PCB: Filter 120 V RSPL Both 3.2.08 9 56609701 3YS4011-1315P1[...]

Page: 174 Service Guide ML520/521 Chapter B Illustrated Parts Listing B.2.04 Printer Unit Item Okidata P/N Oki-J P/N Description Comments Refer to B.1.02 Disassembly Procedure 1 53563101 3PA4025-3720G1 Frame: Main (Narrow) RSPL 520 3.2.30 1 53563201 3PA4025-3721G1 Frame: Main (Wide) RSPL 521 3.2.30 2 50804601 3PP4025-3315P1 Lever: Bottom Paper End [...]

6 56627201 3PB4025-3356P1 Cord: Connection Line Feed RSPL Both 3.2.21 7 56510302 3PB4025-3357P2 Motor: Line Feed Assembly RSPL Both 3.2.21 8 51228601 3PB4055-2893P1 Gear: Line Feed Idle RSPL Both 3.2.21 9 51010301 3PA4025-3387G1 Plate: Left Ground RSPL Both 3.2.16 10 50923001 3PP4025-3320P1 Spring: Leaf (Narrow) RSPL 520 3.2.26 10 50923101 3PP4025-[...]

Page: 175 Service Guide ML520/521 Chapter B Illustrated Parts Listing B.2.05 Printer Unit Item Okidata P/N Oki-J P/N Description Comments Refer to B.1.02 Disassembly Procedure 1 53563101 3PA4025-3720G1 Frame: Main (Narrow) RSPL 520 3.2.30 1 53563201 3PA4025-3721G1 Frame: Main (Wide) RSPL 521 3.2.30 2 51228001 4PP4025-3340P1 Gear: Change RSPL Both 3[...]

5 51228201 4PP4025-3353P1 Gear: Idle RSPL Both 3.2.23 6 50805101 2PP4025-3354P1 Lever: Change RSPL Both 3.2.23 7 50923201 3PP4025-3355P1 Spring: Reset RSPL Both 3.2.22 8 51010201 3PP4025-3386P1 Plate: Right Ground RSPL Both 3.2.17 9 50098301 3PA4025-3370G1 Platen Assembly (Narrow) RSPL 520 3.2.19 9 50098302 N/A Platen Assembly (Wide) RSPL 521 3.2.1[...]

Page: 176 Service Guide ML520/521 Chapter B Illustrated Parts Listing B.2.06 Printer Unit Item Okidata P/N Oki-J P/N Description Comments Refer to B.1.02 Disassembly Procedure 1 53563101 3PA4025-3720G1 Frame: Main (Narrow) RSPL 520 3.2.30 1 53563201 3PA4025-3721G1 Frame: Main (Wide) RSPL 521 3.2.30 2 50922901 4PP4025-3316P1 Spring: Front Pressure ([...]

4 53341101 4PP4025-3317P1 Holder: Front Roller RSPL Both 3.2.28 5 53341202 4PP4025-3327G1 Roller: Front Pressure RSPL Both 3.2.28 6 51227801 3PP4025-3318P1 Shaft: Front Release Gear (Narrow) RSPL 520 3.2.27 6 51227901 3PP4025-3505P1 Shaft: Front Release Gear (Wide) RSPL 521 3.2.27 7 50097301 N/A Pan: Paper (Narrow) RSPL 520 3.2.27 7 50097401 1PP402[...]

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. ( http://bpx.okidata.com)[...]

Page: 177 Service Guide ML520/521 Chapter B Illustrated Parts Listing B.2.07 Carriage Assembly Item Okidata P/N Oki-J P/N Description Comments Refer to B.1.02 Disassembly Procedure 1 50707401 3PP4025-3431P1 Clamp: Head RSPL Both 3.2.02 2 53562801 3PP4025-3430P1 Protector: Ribbon RSPL Both 3.2.03 3 51228501 3PA4025-3406G1 Gear: Case (Assembly) RSPL [...]

4 56729601 224A1285P0400 Connector: PC HD40 RSPL Both 3.2.10 5 53343001 4PP4025-3433P1 Holder: Connector (L) RSPL Both 3.2.11 6 53343101 4PP4025-3434P1 Holder Connector (R) RSPL Both 3.2.11 7 56510401 4YA4025-3250G1 Motor: Space (Assembly) RSPL Both 3.2.11 8 53343301 4PA4025-3719G1 Guide: Roller Assembly Both Inc. 9 10 11 3.2.11 9 53341901 4PP4025-[...]

Page: 178 Service Guide ML520/521 Chapter B Illustrated Parts Listing B.2.08 Options Item Okidata P/N Oki-J P/N Description Comments Refer to B.1.02 Disassembly Procedure 1 70022501 N/A Kit: Single Bin CSF 5000 Narrow Option 520 N/A 1 70022701 N/A Kit: Single Bin CSF 5001 Wide Option 521 N/A 2 70023001 N/A Kit: Pull Tractor Narrow Option 520 N/A 2 [...]

3 70023101 N/A Kit: Push Tractor (Bottom) Wide Option 521 N/A 4 70023301 N/A Kit: Roll Paper Stand Option 520 N/A 5 70000803 N/A Kit: Parallel Interface Plug'n'Play Accessory Option Both N/A 6 70012801 N/A Kit: RS232-C Serial Interface Option Both N/A 7 56412501 4YB4049-7031P1 Transformer 230-240V (ML520) Option RSPL 520 N/A 7 56412502 4Y[...]

Page: 179 Service Guide ML520/521 Chapter B Illustrated Parts Listing B.2.09 Option Parts Item Okidata P/N Oki-J P/N Description Comments Refer to B.1.02 Disassembly Procedure 1 50097901 N/A Tractor: Pull and Bottom Assembly (Right) Option RSPL Both N/A 2 50098001 4PA4025-3608G1 Tractor: Pull and Bottom Assembly (Left) Option RSPL Both N/A 3 500981[...]

8 53067501 1PP4053-2575P1 Cover: Side (Right) Cut-Sheet Feeder Option RSPL Both N/A 9 53480901 1PP4043-1891P4 Supporter: Front Sheet (W) Cut-Sheet Feeder Option RSPL 521 N/A 9 53562901 1PP4053-2576P1 Supporter: Front Sheet (N) Cut-Sheet Feeder Option RSPL 520 N/A 10 53563001 4PP4053-2547G1 Shoe: Brake Cut-Sheet Feeder Option RSPL Both N/A 11 559373[...]

Page: 180 Service Guide ML520/521 Chapter B Illustrated Parts Listing B.2.10 Consumables 52107001 N/A Ribbon: Black Consumable Both 3.2.02 Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)[...]

Page: 181 Service Guide ML520/521 Chapter B Illustrated Parts Listing B.2.11 Packing Materials Item Okidata P/N Oki-J P/N Description Comments Refer to B.1.02 Disassembly Procedure 1 53565101 N/A Box: Graphic (ML520) RSPL 520 N/A 1 53565201 N/A Box: Graphic (ML521) RSPL 521 N/A 2 53565401 N/A Foam: Molded (Left) RSPL Both N/A 3 53565402 N/A Foam: M[...]

Page: 182 Service Guide ML520/521 Chapter B Illustrated Parts Listing B.2.12 Documentation Item Okidata P/N Oki-J P/N Description Comments Refer to B.1.02 Disassembly Procedure 1# 58229401 N/A Kit: ML520/521 Service Training Document Both N/A 1# 58229402 N/A Kit: ML520/521 Service Training Document Both N/A 1# 58229403 N/A Kit: ML520/521 Service Tr[...]

8 B 59256802 N/A Handbook: Printer Document Part of 2 B N/A 9 59258401 N/A Manual: Maintenance Document Both N/A 10 59261000 N/A Manual: Troubleshooting Document Both N/A 11 59254001 N/A Product Specifications Document Both N/A * To order Marketing Literature, complete an Okidata Marketing Literature Order Form. Fax the completed form to Okidata Ma[...]

Page: 183 Service Guide ML520/521 Chapter B Illustrated Parts Listing B.2.13 Service Training Kit Revision List P/N 58229401 Microline 520/521 Service Training Kit This kit was replaced by P/N 58229402. Items in the training kit (except for the Printer Handbook) are NOT available separately. Item Okidata P/N Oki-J P/N Description Comments Refer to [...]

16 A 52063202 N/A Label: Service Videotape Case Document N/A 17 A 52063203 N/A Label: Service Videotape Front Document N/A 18 A 52063204 N/A Label: Service Videotape Spine Document N/A 19 A 57517101 N/A Red Vinyl Case (VHS Videotape) Document N/A 20 A 53533001 N/A Storage Box Document N/A P/N 58229402 Microline 520/521 Service Training Kit This kit[...]

Item Okidata P/N Oki-J P/N Description Comments Refer to B.1.02 Disassembly Procedure 1 C 58229403 N/A Kit: ML520/521 Service Training Document Both N/A 2 C 52063206 N/A Label: Box Document Both N/A 3 C 58090403 N/A Read Me First Document Both N/A 4 C 59257803 N/A Service Handbook Document Both N/A 5 C 59256802 N/A Printer Handbook Document Both N/[...]