Agilent Technologies 2948 инструкция обслуживания

Agilent Technologies, Inc 24001 E Mission Liberty Lake, WA 99019 www agilent corn .. ..':.+:.. Agilent Technologies ..e:*.. . ' Innovating the HPWay June 8,2000 Dear Customer, As of November 1, 1999, four of Hewlett-Packard's businesses, test and measurement, semiconductor products, health care solutions, and chemical analysis became[...]

HP 8904A MULTIFUNCTION SYNTHESIZER (Including Options 001, 002, 003, and 004) Service Manual SERIAL NUMBERS This manual applies directly to instruments with serial numbers prefixed SEW PREFIXES 2712A to 2948A and all MAJOR changes that apply to your instrument. rev.OlJUL91 For additional important information about serial numbers, refer to "IN[...]

1 Regulatory Information (Updated March 1999) 1[...]

Regulatory Information (Updated March 1999) Safety Considerations GENERAL This product and related documentation must be reviewed for familiarization with safety markings and instructions before operation. This product has been designed and tested in accordance with IEC Publication 1010, "Safety Requirements for Electronic Measuring Apparatus,[...]

Regulatory Information (Updated March 1999) Safety Considerations for this Instrument ~ WARNING This product is a Safety Class I instrument (provided with a protective earthing ground incorporated in the power cord). The mains plug shall only be inserted in a socket outlet provided with a protective earth contact. Any interruption of the protective[...]

Regulatory Information (Updated March 1999) To prevent electrical shock, disconnect instrument from mains (line) before cleaning. Use a dry cloth or one slightly dampened with water to clean the external case parts. Do not attempt to clean internally. Ventilation Requirements: When installing the product in a cabinet, the convection into and out of[...]

Model 8904A Contents CONTENTS Section 6 . Replaceable Parts Introduction to This Section ............................................ 6.1 Reference Designations and Abbreviations Used in This Manual ........................ 6.1 Replaceable Parts List ................................................ 6.1 Ordering Parts ...............................[...]

Model 8904A Contents Section 8 . Service (cont’d) How to Restore the Serial Number in a Replacement A2 Digital Assembly ................ 8-43 How to Restore Options 001 and 003 in a Replacement A2 Digital Assembly How to Replace the Memory Backup Battery ............................... 8-48.1 Service Sheets 1 through 4 (schematics) ..............[...]

Model 8904A Replaceable Parts Section 6 REPLACEABLE PARTS 6-1. INTRODUCTION TO THIS SECTION This section contains information for ordering parts. Table 6- 1 lists reference designations, and Table 6-2 lists abbreviations that are used in the Replaceable Parts List. Table 6-3 lists all replaceable parts in the instrument. Table 6-4 contains the name[...]

Replaceable Parts Model 8904A How to Order To order a part in the Replaceable Parts List, call or write the nearest Hewlett-Packard Sales Office. Have the following information ready to speed the ordering process: 1. The Hewlett-Packard part number with the check digit. (The check digit will ensure accurate and 2. The quantity required. 3. An appro[...]

Model 8904A Replaceable Parts nable 6-1. Reference Designations AT . B .. BT . c .. CP . CR . DC . DL . , DS . A ........ assembly ..... attenuator; isolator; ............. fan: motor ................ battery .............. capacitor ............... coupler ........... diode; diode thyristor: varactor ...... directional coupler .............. delay[...]

Replaceable Parts Model 8904A Table 6-2. Abbreviations (2 of 2) MOD .... modulator MOM ........... momentary device) mV ................ millivolt mVac ........... millivolt, ac mVpp ....... millivolt, peak- mVrms ......... millivolt, rms mW ............... milliwan MUX ............. multiplex MY ................. mylar & ............ microampe[...]

Model 8904A Reference Designation A1 2 71ZA to 291 7A 2025% and abwo AI w1 Alt A2 2712A to 2942A A2 A2 2048A and ah A2 A2 2712A to 2M2A A2BTl 2712A to 2942A A2BTl 2 712A to 2 732A A2u12 i. AZUlZt A2U13 t 2737A to 2942A A2U13 2737A to 294OA A2u12 2742A and ah A2u12 2737A andabwo A2U13 HPPart C Qty. Number D 08904-60201 4 1 0890480102 4 1 08904-69102[...]

Replaceable Parts Model 8904A Reference Designation A3 2712A to 2942A A3 A3 2948A and abow A3 A3 A3C1 A3C2 A3C3 A3C4 A3C5 A3C6 A3C7 A3C8 A3C9 A3C10 A3C11 A3C12 A3C13 A3C14 A3C15-27 A3C28 A3C29 A3C30 A3C31 A3C32 A3C33 A3C34 A3C35 A3C36 A3C37 A3C38 A3C39 A3C40 A3C41 A3C42 A3C43 A3C44 A3C45 A3C46 A3C47 A3C48 A3C49 A3C50 A3C51 A3C52-63 A3C64 A3C65-70 A[...]

Model 8904A Replaceable Parts Table 6-3. Replaceable Parts Reference Designation HP Part Number C D Mfr* Mfr. Part Number Code Description NOT ASSIGNED CAPACITOR-FXD .1UF +-lo% 50VDC CER CAPACITOR-FXD .1UF +-1O% 5OVDC CER NOT ASSIGNED CAPACITOR-FXD .OlUF +-lo% lWVDC CER CAPACITOR-FXD .1 UF +-1O% 5OVDC CER CAPACITOR-FXD .OlUF +-lo% 1 WVDC CER CAPACI[...]

Replaceable Parts Model 8904A Table 6-3. Replaceable Parts Reference Designation A3C403 A3C404 A3C405 A3C406 A3C407 A3C408 A3C409 A3C410 A3C41 1 A3C412 A3C413 A3C414-420 A3C421 A3C422 A3C423 A3C424 A3C425 A3C426 A3C425-430 A3C431 A3C432 A3C433 A3C434 A3C435 A3C436 A3C437 A3C438 AX439 A3C440 MC441 A3W2 A3C443 A30614 A3C445 A3C446 A3C447 A3C448 A3C44[...]

Model 8904A Replaceable Parts %Me 6-3. Replaceable Parts Reference Designation A3CRlO-16 A3CR17 MCRl8 A3CRl9-25 A3CR26 A3CR27 A3CR28-201 A3CR2M A3CR203 A3CR204 A3CR205 A3CR206 A3CR207 A3CR208 A3CR209 A3CR210 A3CR211 A3CR212 A3CR213-299 A3CR300 A3CR301 A3CR302-403 A3CR404 A3CR405 A3CR406 A3CR407 A3CR408 A3CR409 A3CR410 A3CR411 A3CR412414 2712A to 27[...]

Replaceable Parts Model 8904A Table 6-3. Replaceable Parts Reference Designation A3CR429 A3CR430 A31 A32 A33 A34 A35 A36 A37 2712A to 2942A J8 2948A and abom A3J8 A394200 A3201 A3202J399 A3400 A3401 A3K1 A3K2 A3K3 A3K4 A3K5 A3K6 A3K7 A3K8 A3K9 A3K10 A3K11 A3K12-400 A3K401 A3K402 A3K404 A3L1 A3L2 A3L3 A3L4 A3L5 A3L6 A3L7 A3L8 A3L9 A3L10 A3L11 A3L12 [...]

Model 8904A Replaceable Parts Table 63. Replaceable Parts Reference Designation HP Part Number C D Mfr. Code Mtr. Part Number QW. Description MMP8 A3MP7 A3MP8 A301 A3Q2 -13 A3014 A301 5 A301BA A3Q17A A301 8A m19A A3m A3Q2lA A3oi232 A3033A A3a34-200 A3(1xlA A30202A A3Qzo3A A30204A A3am5A A30206A A3(1207A A30209 A3021 0 A30208A A30300A A3QjOl A A3Qj0[...]

Replaceable Parts Model 8904A Table 6-3. Replaceable Parts Reference Designation A3R6-8 A3R9 A3R10 A3Rll-39 A3R40 A3R41 A31342 A3R43 A3R44 A3R45 A3R46 A3R47 A3R48 A3R49 A3R50 A3R51 A3R52 A3R53 A3R54 A3R55 A3R56 A3R57 A3R58 A3R59 A3R60 A3R61 A3R62 A3R63 A3R64 A3R65 A3R66 A3R67 A3R68 A3R69 A3R70 A3R71 A3R72 A3R73 A3R74 A3R75 A3R76 A3R77 A3R78 A3R79-1[...]

Model 8904A Replaceable Parts !Cable 6-3. Replaceable Parts Reference Designation HP Part Number C D Mfr. Code Mfr. Part Number Description A3R114 A3R115- 121 A3R122 A3R123 A3R124 A3R125 A3R126 A3R127- 135 A3R136 A3R139 A3R140 A3R141 A3R142 A3R 143 - 200 A3R201 A3R202 A3R203 A3R204 A3R205 A3R206 A3R207 A3R208 A3R209 A3R210 A3R211 A3R212 A3R213 A3R2[...]

Replaceable Parts Reference Designation A3R231 A3R232 A3R233 A3R234-299 A3R300 A3R301 A3R302-399 A3R400 A3R401 A3R402 A3R403 A3R404 A3R405 A3R406 A3R407 A3R408 A3R409 A3R41 0 A3R411 A3R412 A3R413 A3R414 A3R415 A3R416 A3R417 A3R418 A3R419 A3R420 A3R421 A3R422 A3R423 A3R424 A3R425 -445 A3R446 A3R447 A3R448 A3R449 A3R450 A3R451 A3R452 A3R453 A3R454 A3[...]

Model 8904A Replaceable Parts Table 6-3. Replaceable Parts Reference Designation HP Part Number C D Mfr. Code Mfr. Part Number Description A3R458 A3R459 A3R460 A3R461 A3R462-465 A3R466 A3R467 A3R466 A3R469 A3R470 A3R471 A3R472-489 A3R490 271ZA to 2747A A3R491 2817A and dove A3R491 A3R492 27IZA to 2747A A3R493 A3R494 A3R495 2817A and dove A3R493 A3R[...]

Replaceable Parts Model 8904A Table 6-3. Replaceable Parts Reference Designation HP Part Number C D Mfr. Code Mfr. Part Number Description A3U6 A3U7 A3U8 A3U9 A3U 10 1826-1013 1858-0047 1826-1 049 18550047 0 D/A 12-1/2-BIT 24-DIP-C BPLR NOT ASSIGNED TRANSISTOR ARRAY 16-PIN PLSTC DIP IC OP AMP PRCN 8-DIP-C PKG TRANSISTOR ARRAY 16-p~~ PLsrc DIP 24355[...]

Model 8904A Replaceable Parts nble 6-3. Replaceable Parts Reference HPPart C Description Designation Number D A4 A4 A5 A5 A6 08904-61001 4 1 POWERSUPPLYASSEMBLY 1-1197 8 1 LCDASSEMBLY 271211 To 2942A A6 NOT ASSIGNED 2948A und above A6 0890460104 6 1 TRANSFORMERBOARD (ADDED FOR OPTION 006) A6C1 A6C2 A6C3 A6J1 A612 A6J3 AW4 A6J5 A6R1 A6R2 A6R3 A6R4 A[...]

Replaceable Parts nble 6-3. Replaceable Parts Reference HPPart C Description Designation Number D w’ A7-A9 NOT ASSIGNED Model 8904A Mfr- Mfr. Part Number Code A10 Note: The A1 0 and A3 Assemblies are identical. Refer to A3 for individual component part numbers. tRefer to Section 7 for update information 6-18 *Factory Selected Component (Refer to [...]

Model 8904A Reference HPPart C atv. Design at i o n Number D B1 F1 2712A to 2917A SI 2923A and hue SI T1 2712A to 2917A Wl 2923A and &ow WI w2 w3 w4 w5 W6 w7 W8 w9 w10 w11 w12 W13 %ble 6-3. Replaceable Parts Description Miscellaneous Parts 08904-61010 5 1 FANASSY 12VDC 21 104003 0 1 FUSE 3A 250V NTD 1.25X.25 UL (INCLUDED WHEN ORDERING W1) 3101-[...]

Replaceable Parts Model 8904A Reference Designation W14 W15 W16 W17 2932A to 2942A WI8- w25 2948A and &ow W18 WI9 w20 w21 W22 w23 w24 w25 HPPart C Number D 0890461004 7 0890461006 9 0890461008 1 08904-61008 1 50614837 4 5061-4837 4 08904-61015 0 08904-61015 0 08904-61007 0 08904-61007 0 08904-61007 0 0890461007 0 QW 1 1 1 1 1 1 1 1 1 1 1 1 +Ref[...]

Model 8904A Replaceable Parts Reference Designation 1 2712A lo 2u42.4 2 2H8A and abe 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 10 20 21 22 23 24 25 26 27 28 29A 30 31* 32 33 34 35 HPPart Qty. Number D 0890440010 7 1 08904-61012 7 1 08904-61014 1 1 0361-1020 2 4 0361-1020 2 0361-1020 2 0361-1020 2 1252-2245 5 2 1252-2245 5 21904007 2 2 21000007 2 0[...]

Replaceable Parts Model 8904A able 6-3. Replaceable Parts Reference Designation 2712A to 2917A 36 t 37 t 38 t 39 t 2923A and abow 36 37 38 39 HP Part Number C D Mfr- Mfr. Part Number Code w. Description SEE SECTION 7 FOR FRONT PANEL RETROFIT KIT SEE SECTION 7 FOR FRONT PANEL RETROFIT KIT SEE SECTION 7 FOR FRONT PANEL RETROFIT KIT SEE SECTION 7 FOR [...]

Model 8904A Replaceable Parts Table 63. Replaceable Parts Reference Designation HPPart C Number D Mfr. Code Mfr. Part Number QW. Description 66 57'5 68A 69 59 60 60 69604132 1 PLUGHOLE SOD NOT ASSIGNED NOT ASSIGNED NWHM-DBLCHAM l5B232-THD (USED FOR OPTION 002) NWHEX-DBLCHAM l5B232-THD (USED FOR OPTION 006) NWSPCLY ly32-32-THD .l-IN-THK .562-WD[...]

Replaceable Parts Model 8904A Table 6-3. Replaceable Parts Reference Designation 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 HP Part Number 051 51 234 0361 -1 265 0361-1 265 0361-1265 0361-1265 5021-8415 0515-1860 051 51 860 0515-1860 0515-1860 051 51 860 14000249 1[...]

Model 8904A Replaceable Parts Table 6-3. Replaceable Parts Description Reference Designation 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 27I2A to 2817A I39 2822A and ubooe 139 Number HPPart 0380-1914 3 SPACER-RND 19-MM-LG 5.6MM-ID 1 OMM-OD 0380-1929 0 1 SPACER-RND 19-MM-LG CMM-ID 3.5MM-THO 14004249 0 1 CABLE TIE .062[...]

Replaceable Parts Model 8904A lbble 6-3. Replaceable Parts Description HPPart E sty. Reference Designation Number 2712A to 291 7A I40 141 2923A and above I40 I41 NOT ASSIGNED NOT ASSIGNED NOT SEPARATELY REPLACEABLE NOT SEPARATELY REPLACEABLE 2912A to 291 7A 142-145 NOT ASSIGNED 2923A and aboue 142 0890600022 1 1 LINE SWITCH BRACKET 143A 05152028 6 [...]

I'ZZ-9 68AON 1O'naJ[...]

Replaceable Parts Model 8904A L .' Figure 6-1. Main Deck Assembly - Top, (2923A and above) rev. 01 NOV89 6-22.4[...]

Model 8904A Replaceable Parts Figure 6-1. Main Deck Assembly - Top, Option 005 (2948A and above) rev.30NOV89 6-23[...]

Replaceable Parts Model 8904A Figure 6-2. Main Deck Assembly - Bottom reu.3ONOV89 6-24[...]

Replaceable Parts Model 8904A Figure 6-2. Main Deck Assembly - Bottom, Option 006 (2948A and above) rev.30NOV89 6-24.1[...]

Replaceable Parts Model 8904A /; W 0 W W wl Figure 6-3. Front Panel Assembly, (2712A to 291 7A), See Section 7 for Front Panel Retrofit Kit. 6-24.2 reu.30NOV89[...]

Model 8904A Replaceable Parts Figure 6-3. Front Panel Assembly, (2923A and above) reu.30NOV89 6-24.3[...]

Model 8904A Replaceable Parts Figure 6-3. Rent Panel Assembly, Option 006 (2948A and above) reu.30NOV89 6-25[...]

Replaceable Parts Model 8904A Figure 6-4. Rear Panel Assembly rev. 30NO V89 6-26[...]

Model 8904A Replaceable Parts Figure 6-4. Rear Panel Assembly, Option 005 (2948A and above) rev. 30N0 V89 6-26.1[...]

Model 8904A Replaceable Parts Figure 6-5. Covers, Labels, and ROMs rev.ZSSEP88 6-27[...]

Replaceable Parts Model 8904A Figure 6-6. Output Cables (1 of 2) reu.30NOV89 6-28[...]

Model 8904A Replaceable Parts Q Figure 6-6. Output Cables, Option 005 (29484 and above) (2 of 2) rev. 30N0 V89 6-29[...]

H P 8 9 0 4 A Table of Contents TABLE OF CONTENTS Section 7 Instrument Changes Introduction to This Section ............................................ 7.1 Option Conversions ................................................. 7.1 Instrument Modifications .............................................. 7.2 Front-To-Rear-Panel Output Conversion ......[...]

Model 8904A Instrument Changes Section 7 INSTRUMENT CHANGES 7-1. INTRODUCTION TO THIS SECTION This section contains instrument modification recommendations and procedures that could improve the performance and reliability of your instrument. Refer to Instruments Covered by This Manual in section 1 of the HP 8904A Operation and Calibration Manual fo[...]

Instrument Changes Model 8904A Serial Prefix 2737A and below 2747A and below 281 7A and below 291 7A and below To retrofit Option 006 (balance output), order HP 11837A from your local Hewlett-Packard Sales office. Only instruments with serial prefix 2948A and above can be retrofit with this option. The added balanced output will replace one of the [...]

Model 8904A Instrument Changes 7-4. FRONT-TO-REAR-PANEL OUTPUT CONVERSION Description This procedure describes how to convert an instrument with front-panel output connectors (that is, a standard instrument) to one with rear-panel connectors (that is, Option 004). The procedure applies to instruments with one pair of outputs or two (that is, Option[...]

Instrument Changes Model 8904A Cable Routing 1. Refer to figures 7-1, 7-2 and 7-3. Remove the BNC connector ends from the front panel one at 2. After all of the connectors have been transferred to the rear panel, secure the cables to the side 3. Install one new lock washer and one new nut on each connector. 4. Tighten the nuts on the BNC connectors[...]

Model 8904A Instrument Changes Option Quantity 7-5. REAR-TO-FRONT-PANEL OUTPUT CONVERSION Description HP Part Number Description Option Quantity Standard 2 Option 002 4 3 This procedure describes how to convert an instrument with rear-panel output connectors (that is, Option 004) to one with front-panel connectors (that is, a standard instrument). [...]

Instrument Changes Model 8904A Cable Routing 1. Refer to figures 7-1, 7-2 and 7-3. Remove the BNC connector ends from the rear panel one at a time and insert them into the corresponding openings in the front panel. 2. After all of the connectors have been transferred to the front panel, loop the cables and secure them to the front of the deck using[...]

Instrument Changes Model 8904A Figure 7-1. Ront Panel Output Hardware h Figure 7-2. Rear Panel Output Hardware rev.lSDEC89 7-7[...]

Instrument Changes Model 8904A w5 Figure 7-3. Output Cable Routing (ALL Options) 7 -8 rev. 15DEC89[...]

Model 89048 Instrument Changes 7-6. FIRMWARE UPDATES (A2U12 AND A2U13) The -ware is changed whenever anomalies are found in the instrum ent’s operation which can be corrected by altering the Controller’s program. Firmware is also changed to add new features, which may only be changes in the program, or which may also result from instrument hard[...]

Instrument Changes Model 8904A Cable Tie Wire (Green/Yellow) 7-7. MODIFICATION FOR POSSIBLE GROUND WIRE SHOCK HAZARD 0360-0036 1400-0249 81 50-291 9 (Serial Prefix 2737A and below) On some instruments with serial prefix 2737A and below, the grounding wire from the rear-panel line socket to the metal chassis may not have been wrapped and soldered in[...]

Model 8904A Instrument Changes Checking for the Shock Hazard 1. Unplug the power cord from its rear-panel socket. 2. Remove the instrument’s top cover by backing out the screw in the center of the rear edge of the cover. This is a captive screw and will cause the cover to push away from the frame. 3. Refer to figure 7-4. Locate the ground wire. I[...]

Instrument Changes Model 8904A GOOD WRAPPING Wire is mechanically secure prior to soldering. The wire wrap is at least three quarters to one full turn. POOR WRAPPING (1) Wire is not mechanically secure prior (2) Wrap is less than three quarters turn. (3) Wrap exceeds one full turn. to soldering. ~~ ~ ~~ ________~ Figure 7-5. Ground Wire Wrapping Re[...]

Model 8904A Instrument Changes ~~ 0698-0085 0757-01 99 1901 -0880 NOTE 0 2 Fixed Resistor, 261 OR 3 2 Fixed Resistor, 21.5 kR 7 4 Diode It is possible that the 22 gauge black wire may break while replacing the new ground wire. If it does, strip 8 mm (5116 inch) of insulation from it and properly wrap and solder it to a second new lug. 10. Replace t[...]

Instrument Changes Model 8904A 7-9. MODIFICATION FOR POTENTIAL POWER SUPPLY SHORT (Serial Prefix 2817A and below) A problem has been noted in HP 8904A Multifunction Synthesizers with Option 002 (a second output) and with serial prefix 2817A and below. In these instruments it is possible for the heatsinks on the output transistors on the A10 Output [...]

Model 8904A Instrument Changes 7-1 1. MODIFICATION FOR FRONT PANEL ASSEMBLY (Serial Prefix 2712A to 2917A) INTRODUCTION HP part number 08904-61023 contains the parts to replace the front panel in HP 8904A Multifunction Synthesizers with serial prefix 2917A or below. The front-panel keys in these instruments may have a tendency to intermittently sta[...]

Instrument Changes Model 8904A Removing the Front Panel 3. Unplug the two connectors on the top front edge of the A2 Digital Assembly that are attached to the A5 LCD Display. (Refer to figure 6-3. The two cables are labeled as P/O A5.) 4. Remove the top trim strip (item 67 in figure 6-5) and two side strips (items 61 and 62) from the front-panel fr[...]

Model 8904A Instrument Changes Installing the Front Panel 16. Remove any existing, unneeded hole plugs from the new front-panel assembly. 17. Install the line switch bracket supplied in the kit (HP 08904-00022, item 142 in figure 7-6, Detail A herein) on to the line switch using the two Pozidriv screws supplied in the kit (HP 0515-2028, items 143 a[...]

Instrument Changes Model 8904A Figure 7-6.Dont-Panel Assembly, (2923A and above) 7-18 Firmware UpdatesIHardware Modifications reu.15DEC89[...]

HP8904A Table of Contents TABLE OF CONTENTS Section 8 Service Introduction To This Section ............................................ 8-1 How The Section Is Organized ........................................... 8.1 Safety Considerations ................................................ 8.1 Service Tools, Helps, and Information ....................[...]

Model 8904A Service Section 8 SERVICE 8-1. INTRODUCTION TO THIS SECTION This section contains information for troubleshooting and repairing the Multifunction Synthesizer. Included are principles of operation, troubleshooting checks, and schematic diagrams for selected circuits. 8-2. HOW THE SECTION IS ORGANIZED Section 8 contains the following: 0 S[...]

Model 8904A Service I WARNING I Proper grounding of the instrument. Any interruption of the protective (grounding) conductor (inside or outside the instrument) or disconnection of the protective earth terminal will create a potential shock hazard that could result in personal injury. Grounding one conductor of a two conductor outlet is not sufficie[...]

Model 8904A Service 8-4. SERVICE TOOLS, HELPS, AND INFORMATION Printed Circuit Board Extractor A Printed Circuit Board Extractor (HP 08904-00012) is supplied as part of this manual. It eases removal of the A3 and A10 Output Assemblies. It hooks under the board or the metal board shield so the board can be pulled off the mounting studs. Assembly, Pa[...]

Service Model 8904A Table 8-1. Schematic Diagram Notes (1 of 11) with adjacent Test points: symbols number indicates are numbered for easy circuit-path correlation to schematic continuation to diagrams. procedures. another service Plug-in sheet (3. in and component location diagrams. Connection to inf ormat ion; this example). circuit signifies num[...]

Model 8904A Service Table 8-1. Schematic Diagram Notes (2 of 11) Values for all components are marked in units of farads, henries, and ohms unless otherwise specified. * 0 -0- F- U c m -4 12 Asterisk denotes a factory-selected value. Value shown is typical. See Section V. Tool-aided adjustment. Encloses front-panel designation. Encloses rear-panel [...]

Service Model 8904A Table 8-1. Schematic Diagram Notes (3 of 11) -L 4 ,, J. ,, 1 ,, 322 'I Y - T 4 Indicates multiple paths represented by only one line. Letters or names identify indi- vidual paths. Numbers indicate number of paths represented by the line. Coaxial or shielded cable. Ferrite bead. (Increases the self-inductance of the conducto[...]

Model 8904A llzble 8-1. Schematic Diagram Notes (4 of 11) Service DIGITAL SYMBOLOGY REFERENCE INFORMATION Input and Output Indicators Implied Indicator-Absence of polarity indicator (see below) implies that the active state is a relative high voltage level. Absence of negation indicator (see below) im- plies that the active state is a relative high[...]

Service Model 8904A Table 8-1. Schematic Diagram Notes (5 of 11) c 8 21 zm =1 =m x-Y (Functional Labels) MUX DEMUX CPU DIGITAL SYMBOLOGY REFERENCE INFORMATION Combinational Logic Symbols and Functions Summing Junction-Outputs added together at a common point. AND-All inputs must be active for the output to be active. OR-One or more inputs being act[...]

Model 8904A Service Table 8-1. Schematic Diagram Notes (6 of 11) In G nJ--Ln FF T S R J K D +m -m -m -m (Functional Labels) mCNTR DIGITAL SYMBOLOGY REFERENCE INFORMATION Sequential Logic Functions Monostable-Single shot multivibrator. Output becomes active when the input be- comes active. Output remains active (even if the input becomes inactive) f[...]

Service Model 8904A Table 8-1. Schematic Diagram Notes (7 of 11) DIGITAL SYMBOLOGY REFERENCE INFORMATION Sequential Logic Functions (Cont’d) Register-Array of unconnected flip-flops that form a simple register or latch. Shift Register-Array of flip-flops that form a register with internal connections that permit shifting the contents from flip-fl[...]

Model 8904A Service llable 8-1. Schematic Diagram Notes (8 of 11) DIGITAL SYMBOLOGY REFERENCE INFORMATION Miscellaneous Schmitt Trigger-Input characterized by hysteresis; one threshold for positive going signals and a second threshold for negative going signals. n- Active Active State-A binary physical or logical state that corresponds to the true [...]

Service Model 8904A L Table 8-1. Schematic Diagram Notes (9 of 11) L H AND GATE B L L OR GATE H H L L L EXCLUSIVE-OR GATE OPEN COLLECTOR OUTPUTS (TTL) 1 I +V .' ,' I - EXTERNAL PULL-UP RES1 STOR NAND GATE H H L H H OR GATE WITH INVERTED INPUTS NOR GATE ABX B AND GATE WITH INVERTED INPUTS "ax B BUFFER X Wl L H INVERTER OPEN EMITTER OU[...]

Model 8904A Service Table 8-1. Schematic Diagram Notes (10 of 11) €3 Active High Input I Active High Output 97 Active Low Input Active I Low Output ACTIVE LEVELS C A-L ACTIVE HIGH inputs and outputs are indicated by the ab- ACTIVE sence of the polarity indicator symbol. I LEVEL I ACTIVE LOW inputs and outputs are indicated by the pres- < + enc[...]

Service Model 8904A Table 8-1. Schematic Diagram Notes (11 of 11) AND OR ENABLE TRANSMISSION CONTROL The input that controls or gates other inputs is labeled with a C or a G, followed by an identifying number. The controlled or gated input or output is labeled with the same number. In this example, 1 is controlled by G1. When a V input is active, t[...]

Model 8904A Service PRINCIPLES OF OPERATION OVERALL What the Multifunction Synthesizer Can Do The HP 8904A Multifunction Synthesizer is a general purpose function generator which can output complex signals based on combinations of six waveforms: sine sawtooth triangle Control over these signals includes: frequency, amplitude, and phase. square nois[...]

Service Model 8904A CHANNEL A I PHASE 7 P LATCH P -0 C’ c- ‘L FREOUENCY 6 FREO DATA 9 0 Figure 8-1. Conceptual Block Diagram of a Standard Instrument CLOCK + The standard instrument has only one channel-Channel A. Channel A can output one of the six available waveforms. Four of the waveforms (sine, sawtooth, triangle, and square) are periodic a[...]

Modei 8904A Service In many ways the figure resembles an analog function generator, and it may be helpful at times to visualize DWSIC operation using this analogy. (For example, the Waveform Table is analogous to an analog shaping circuit.) However, in the DWSIC all signal lines carry signal information as binary codes. Thus, the “waveforms” sh[...]

Service Model 8904A P=3 is an interesting case. The count sequence (in decimal) is 0, 3, 6, 9, 12, 15, 2, 5, 8, 11, 14, 1, 4, 7, 10, 13, 0, etc. The Latch outputs three uneven staircases that repeat every 16 clock periods. In general, if P is not 0 but is small compared to the number of possible states (16 in the current example), the Latch outputs[...]

Model 8904A Service I -- 0 :t -1 3- 4 BITS 5 BITS 6 BITS ~ ~ ~ ~ ~~ Figure 8-5. The Output of the Waveform Table with Data Bus Widths of 4, 5, and 6 Bits With a four-bit data bus, the poor resemblance to a sine wave is apparent. With only four-bit quantization, the resolution is very coarse. A vast improvement is made by increasing the number of qu[...]

Service Model 8904A r ~ - OUTPUT! I * t LEVEL CHANNEL A PULSE t 'L FREOUENCY _+_o Lt- PULSE SUM 1 LEVEL p LEVEL q LEVEL SUM I PHASE x 'L FREOUENCY CHANNEL B 9 PHASE @ PHASE /L FREOUENCY 0 'L FREOUENCY 0 CHANNEL C CHANNEL D Figure 8-6. Conceptual Block Diagram of an Instrument with Options 001 and 002 8-20 Principles of Operation (Ov[...]

Model 8904A Service D7E SAMPLER f=pjT Figure 8-7. Analog Output Block Diagram Analog Waveform Processing The analog waveform processing block diagram is shown in figure 8-7. Instruments with Option 002 have a second, identical output assembly. The DAC receives digital inputs from the instrument’s controller and converts them to an analog voltage.[...]

Service Model 8904A HP 8904A MULTIFUNCTION SYNTHESIZER r----- 1 I A2 DIGITAL ASSY I HP- I B I I I 10 MHz L - I EXT > 10 MHz REF IN I I - < DISPLAY I I I I I A5 ASSY I -- < LA I A4 POWER SUPPLY ASSY t 1 ~- I OUTPUT (OPT 002 1 DWSIC REF OUT DIGITAL PORT OUTPUTS 1 2 Figure 8-8. Interrelationship of Instrument Assemblies (Serial prefix 2942A a[...]

Model 8904A Service 10 MHz EXT REF IN IP 8904A MULTIFUNCTION SYNTHESIZER 1 r------ 1 A2 DIGITAL ASSY HP-18 I I I REF OUT COMPU OUTPUT (OPT 005) (OPT 005) OUTPUT I-1 RE&{ INPUT I A1 ER I I I DIGITAL - PORT I -p-t' ASSY OUTPUTS Figure 8-8.1. Interrelationship of Instrument Assemblies (Serial prefix 2948A and above) rev. 15DEC89 Principles of[...]

Model 8904A Service A2 DIGITAL ASSEMBLY General The A2 Digital Assembly creates the output waveforms as a series of digital codes (via its DWSIC) and performs the overall control and functioning of the instrument (via its microprocessor). Specific tasks include e e e e e e e 0 e e e e e e e control the instrument’s general operation create the di[...]

Service Model 8904A A3 OUTPUT ASSEMBLY (Service Sheets 1 through 4) General The A3 Output Assembly converts the digitally encoded waveform from the digital waveform synthesis integrated circuit (DWSIC) on the A2 Digital Assembly to a precise and useable analog signal. Instruments with Option 002 have a second Output Assembly (designated A10) which [...]

Model 8904A Service R202 t15V 4 0201 R204 +15V 0202 I c207 R205 TI R206 c208 II I - b - dl 61 c221 CR206 CR203 0205 +bV 0206 FROM CLOCK SYNC U2A (HIGH TRUE) HI - R226 -15V 4) - tI - II - - Figure 8-9. Simplified Diagram of the Sampler Drive Differential input transistors (Q205 and Q206) are driven in complement by the outputs of D flip-flop U2A (th[...]

Service Model 8904A +15V +15v & R213 I II c201 11 DAC-ANLSA’LIPLER r -1 R216 ;+(f; I I I iz L----I + TO DAC-ANLSA’LIPLER r -1 R216 tTHlS LINE IS AT GUARD TRACE POTENTIAL LOW-PASS FILTER Figure 8-10. Simplified Diagram of the Sampler Amplifier Sampler Amplifier The Sampler Amplifier must accurately track the DAC output voltage when the Samp[...]

Model 8904A Service Low-Pass Filters (Service Sheet 2) Precise construction of the analog waveform from the DAC requires careful filtering. Since the samples from the DAC are clocked through at approximately 1.67 MHz, sampling theory dictates that a low-pass filter of approximately 840 kHz or less is required; in practice the 3 dB corner will be le[...]

Service Model 8904A Floating Amplifier Driver and On/Off Switch (Service Sheet 3) The On/Off Switch is opened for 15 ms when the Sharp Cutoff Filter is in and the frequency of the signal is changed to prevent the ringing in the filter from getting to the instrument’s output. The unity-gain, inverting buffer amplifier formed by U403 and U404 isola[...]

Model 8904A Service TROUBLESHOOTING GENERAL The goal of the following troubleshooting procedures is to isolate the fault to a single, replaceable assembly. The instrument assemblies are as follows: 0 A1 Keyboard 0 A2 Digital 0 A3 Output 0 A4 Power Supply 0 A5 Display 0 A6 High Power Output (Installed only in Option 006) 0 A10 Output (Installed only[...]

Service Model 8904A A2 DIGITAL ASSEMBLY TO A3 (OR A10) OUTPUT ASSEMBLY INTERFACE Description The following procedure will help identify whether an instrument failure is due to the analog output circuits or their control inputs. Since the layout of the instrument board assemblies breaks the circuit assemblies along digital-analog lines, this procedu[...]

Model 8904A Service Tools: No. 2 Pozidriv Screwdriver Needlenose Pliers PC Board Extractor (included with Service Manual or order: HP 08904-00013) 1. Turn instrument off, unplug power cord and remove bottom cover. 2. Disconnect ribbon cable, W17. from A1 OJ1 3. Remove hold-down screw and washer from center of A10 Ouput Assembly using Pozidriv scr[...]

Model 8904A Service 116.3 Vdc , (to J1 Pin 28) -16.3 Vdc (to J1 Pin 31) -16.3 Vdc :to ,I: Piis 29 and 30) +!tt.5 Vdc (ts J1 Pins 26 and 27: I I _________-- ~ Serial Prefix ~ 2948A and , above only Not Opt 006 , , , I 'Opt 006, +5. lVdc (to J; Pin 34) 8-32 Figure 8-12. Power Supply Testpoints on A3 or A10 Troubleshooting (Digital/Output Interfa[...]

Model 8904A Service IC on A3 or A10 u5 u5 u5 u5 u5 u5 u4 u4 u4 u4 u4 u4 3b. Clock Checks (Using a Counter) a. If the counter has an external 10 MHz timebase reference input, connect it to the rear-panel 10 MHz REF OUT of the Multifunction Synthesizer. Pin Period 14 19.1 ps 13 38.1 ps 11 76.3 ps 6 153 ps 4 305 ps 3 610 ps 14 1.22 ms 13 2.44 ms 11 4.[...]

Service Model 8904A 4b. Digital-to-Analog Converter Check (Using a Counter) MHz REF OUT of the Multifunction Synthesizer. a. If the counter has an external 10 MHz timebase reference input, connect it to the rear-panel 10 NOTE If the counter does not have an external reference, the readings in the following steps may be off several counts. This does[...]

Model 8904A 5. Miscellaneous Control Checks Service a. On the Multifunction Synthesizer, press SHIFT PRESET. After the instrument presets, key in For A3 Output Assembly For A10 Output Assembly fl (Channel Config.) NEXT NEXT NEXT fl (Channel Config. ) b. Connect a dc coupled, high-impedance oscilloscope or logic probe to the pin of the IC listed in [...]

Service Model 8904A 6. Overvoltage Control Checks a. On the Multifunction Synthesizer, press SHIFT PRESET. After the instrument presets, key in For A3 Output Assembly For A10 Output Assembly SHIFT SERVICE SHIFT SERVICE NEXT NEXT NEXT NEXT f3 (Memory Map Access) NEXT NEXT NEXT NEXT 80 80 f3 (Memory Map Access) NEXT NEXT NEXT NEXT NEXT b. Connect a d[...]

Model 8904A Service u2 u2 nble 8-2. A3 and A10 Interconnections to A2 3 32 U105 4 2 15 U105 12 I Clocks I Pin 14 13 11 6 4 3 14 13 11 6 4 3 i Clocks I Pin IC Pin 13 U34 15 12 u34 12 11 u34 10 10 u34 7 9 u34 5 8 u34 2 7 U36 15 6 U36 12 5 U36 10 4 U36 7 3 U36 5 2 U36 2 ~~ I A3 I J1 and 55 I A2 1 IC U37 u37 u37 u37 u37 u37 U33 u33 u33 u33 u33 u33 A1 0[...]

Service Model 8904A A2 DIGITAL ASSEMBLY TO A1 KEYBOARD ASSEMBLY INTERFACE Description The following procedure will help identify whether a keyboard failure is due to the keyboard itself or the controller. It does this by checking signals on the interface between the two assemblies. If the tests pass but the instrument does not respond to keyboard i[...]

Model 8904A Service NOTE Ignore the beeper and the display as keys are pressed. If pin 8 on A2U4 is always high, a key is probably stuck down. IC on A2 u3 u3 u3 u3 u3 u3 ut u1 u1 u1 u1 u1 Pin 17 15 13 11 a 6 12 13 14 15 16 17 Key Pressed fl, f2, SHIFT, 7, 2 All other keys All other keys f3, f4, e=, kHz V, deg pV All other keys FREQ, PHASE, 0,5, 0 A[...]

Service Key Sequence (None) SHIFT FLOAT 1 OFF (None) SHIFT FLOAT 2 OFF (None) SHIFT OUTPUT 1 OFF (None) SHIFT OUTPUT 2 OFF Annunciator FLOAT 1 FLOAT 2 ON 1 ON 2 Status IC on A2 U38 u35 u2 u2 On Off Pin Level (lTL) 13 L H 13 L H 16 L H 17 L H On Off On Off On Off Model 8904A 3. HP-IB Annunciators Check a. On the Multifunction Synthesizer, press SHIF[...]

Model 8904A Service A2 DIGITAL ASSEMBLY TO A5 DISPLAY ASSEMBLY INTERFACE Description A failure in the A5 Display Assembly can cause the entire instrument to hang up at power up. If this condition is suspected, measure pin 12 of A2U25 or pin 4 of A2U20 with a high impedance, dc coupled oscilloscope. TTL pulses should be seen with 1 ps high and 15 ps[...]

Model 8904A Service A3 OR A10 OUTPUT ASSEMBLY Description The following procedure will assist in locating a fault on the A3 or A10 Output Assembly. It is wise to perform the procedure titled A2 Digital Assembly to A3 (or A10) Output Assembly Interface first to confirm that the fault is indeed on the Output Assembly. NOTE If the instrument has Optio[...]

Model 8904A Service PHASE SYNCHRONIZATION (OPTION 005) Description The operation of the unit-to-unit phase synchronization circuits (Option 005 and serial prefix beginning 2948A only) is checked by monitoring the signals on the rear-panel clock synchronization and phase reset input and output lines. The checks should pinpoint the failure to either [...]

Model 8904A Service HOW TO RESTORE THE SERIAL NUMBER IN A REPLACEMENT A2 DIGITAL ASSEMBLY Description If the A2 Digital Assembly has been replaced by a new or exchange assem,,;, the instrument’s serial number suffix will need to be entered into non-volatile memory (RAM). The suffix is the last five digits of the serial number. For example, the su[...]

Service Model 8904A NOTE The SHIFT key is the blue key. The PRESET key is labeled in blue above the *= key. After 3 seconds the display will time out and read as in step 1. Press SHIFT PRESET as often as needed to view the option and serial display. The displayed option numbers are only two digits (for example, 01) even though the official option n[...]

Model 8904A Service 4. Key in the serial suffix which is printed on the rear-panel serial label, then press ENTER. (For example, if the serial number on the label is 1234A56789, key in 5 6 7 8 9, then press ENTER.) The display should now read: I Press SHIFT f2 to install S/N = 56789. I If S/N is wrong use f3 Reenter f4 Exit. The serial suffix that [...]

Service Model 8904A HOW TO RESTORE OPTIONS 001,003, AND 005 IN A REPLACEMENT A2 DIGITAL ASSEMBLY Description If the A2 Digital Assembly has been replaced by a new or exchange assembly, the instrument’s serial number suffix will need to be entered into non-volatile memory (RAM). (Restoration of the serial number is documented in the previous proce[...]

Model 8904A Service 3. Key in SHIFT SPECIAL 4 8 ENTER SHIFT END. The display should read I **** Option Firmware Installation **** f4 Exit I Enter installation code: NOTE a. The SPECIAL key is labeled in blue above the LAST key. The END key b. After keying in SHIFT SPECIAL, the display should be: fl Special # 0 f2 Status = Off f4 Exit # 0 Last state[...]

Service Model 8904A NOTE a. If a typing error occurs as the Codeword is being entered, the backspace b. If the Codeword is incorrect the display will not list the desired option (em) key can be used to back up to the digit in error. and after the 10 second timeout, the display will read: * HP 8904A Main Selection Level * fl Channel Config. Begin ag[...]

Model 890412 Service HOW TO REPLACE THE MEMORY BACKUP BATTERY Description The battery that backs up non-volatile memory has a limited lifetime. It should be replaced every five years or whenever it shows signs of deterioration. Replacing the battery must be done carefully so as to not interrupt the contents of the RAM. If the RAM looses its content[...]

Service Model 8904A 3. Partially remove the A2 Digital Assembly as follows. (figure 6-1, Main Deck Assembly-Top, may a. Unplug all connectors on the A2 assembly except the two soldered-in coaxial cables. (To remove the front-most keyboard ribbon cable, lift up on its retainer and push the retainer forward.) be helpful.) b. Remove the single Torx sc[...]

Model 8904A Service 5. Desolder the three leads of the backup battery (A2B1) with a solder removal tool and remove the battery. 6a. If the instrument has serial prefix 2942A and below, put the three insulators (HP 3050-0990) on the leads of the new battery (A2B1, HP 1420-0281) and solder in the battery. The bottom of the battery case must not touch[...]

2 c[...]

Model 8904A Service w i m- a- lin n - RAM U14 Capacitor cs Battery B1 Figure 8-12.3. Component Locator for A2 Digital Assembly Detailing the Battery Backup (Serial Prefix 2948A and Above) reu.15DEC89 Troubleshooting (Memory Backup Battery) 8-48.5[...]

Service Model 8904A s- 1 LINE VOLTAGES 1 15VAC-25%. + 1 EA 23EVAC-15%.+10% 48-6bHZ F- 1 LINE NEUTRAL W-18 ASSEMBLY P-4 *PART OF W-12 Figure 8-12.4. Line Voltage Wiring Harness 8-48.6 Troubleshooting (Memory Backup Battery) rev.15DEC89[...]

Model 8904A Service -. X,Y c.3 c.3 c.3 c.3 D,2 D,2 D,2 D,2 D,3 D.3 D,3 D.3 c.1 c.2 c.2 c.3 0.2 D,2 D,3 D.3 D.1 c.2 8.3 8.2 B.3 A3 Component Coordinates (1 of 2) x,y D.2 D,3 D.3 D.2 D.2 0.3 D,3 D,1 8.1 B,1 8.1 8.1 8.1 8.1 A,1 A2 A,2 A2 A2 A.2 A2 A3 A3 A.2 A.3 A3 A3 A2 A2 A3 A,3 A.3 A3 A3 A3 A3 A3 A.3 A3 A3 A.3 A3 A.3 A2 - A3 Component Coordinates (2[...]

r DATA LATCHES 7 c3 'TC 8.81U DIGITAL DATA INPUT TRACK AND HOLD CIRCUIT / / SAMPLER SWITCH 1 1- SAMPLER AMPLIFIER - SAMPLER DRIVE DIGITAL TO ANALOG CONVERTER 7 7 CLOCK SYNC-, G *15MC i1m I I +l5iDC - .-$.. a MER AWLIFIER MW a ss2 I CR2E2 cR293 A- - A f <-Vd., ,/ GUARD TRACE 1.w 51.1 I <+i.88 18.02 Vdo) I I I RZ16 5I.lK I - I POWER SUP[...]

Model 8904A Serv i ce X,Y A,2 8.3 C,2 D,Z D,1 B,Z c,2 B,3 C.3 A2 A.2 A2 A2 A2 A,2 A2 8.1 8.3 D.2 B,3 B,3 A.3 A.3 A.3 A.3 A.3 A.3 A,3 A,3 8.1 A,1 A.l 8.1 8.1 B.1 B.l B.l A,1 A.1 A.l C.2 8.2 D,2 Tpl t COMP X,Y Q402 D.2 (3403 D.3 Q404 D.3 a405 D.Z a406 D,Z a407 ~,3 a408 ~.3 R1 D,1 B,I R2 R3 8.1 R4 8.1 R5 8.1 R9 8.1 R10 B.l R40 A.l R41 A.2 R42 A,2 R43 [...]

Model 8904A Service CHANGES All serial prefixes On the A3 schematic: 0 C230 - Under SHARP CUTOFF (ELLIPTIC) change the value of (2230 to - 1000pF. rev.28MAR89 ss2 8-52.1[...]

ES-8 zss WAS!- (3)30A91- I n I 6'8= NIV9 kl31311dWV OIanV 4 81 I 33(IAS* L 'I I (3IldIll3) JJOlfl3 dWHS dlBLL 4 ME3 T 9NIkl3111J - 31901 N3AILlO ONV SAVl3kIk[...]

Service Model 8904A A3 Component Coordinates (1 of X,Y COMP X,V COMP X,Y C423 C.3 CR300 C.2 8.1 C424 C.3 CR301 8,2 8.1 C425 C,3 CR404 D,2 A. 1 C426 C.3 CR405 D,2 8,1 C431 0.2 CR406 D,3 8.1 8,l C432 0.2 CR407 C,3 C433 0.2 CR408 C,3 A.l A.l C434 D.2 CR409 C.3 C435 D.3 CR410 C,2 A,1 C436 D,3 CR411 C,2 A,1 C437 0.3 CR415 8.2 A.l C438 D.3 CR416 8.2 A.1 [...]

Model 8904A Service All serial prefixes CHANGES On the A3 schematic: 0 R417, R422 - Under FLOATING DRIVER AND ON/OFF SWITCH change the value of R417 and R422 to 75K ohms. rev.28MAR89 ss3 8-54.1[...]

AT3 5 12 - 6 I1 tSVOC +lSVOC 3 - P/O KW1 R117 2 - 8.1U NC NC YQ I I AOOITIONS TO INITIAL INSTRUMENT SETTINGS AHPTO 625 nV MEASURE: 1. 12 Vpp 6, 12, AND 24 dB ATTENUATORS C I10 ,K TO A2 HlSCELLANEOUS CONTROL t5VDC R1C I +5voc ~~ IK +SVOC I t5VDC I *5voc +5voc Ul0E UlSF I )IDOITIONS TO INITIAL INSTRUMENT SETTINOS I I *5 oc +SVDC RlA 1K U10A 9 Ul88 - [...]

Model 8904A Serv i ce A3 Component Coordinates (2 of 2) COMP C423 C424 C425 C426 C431 C432 C433 C434 C435 C436 C437 C438 C440 C441 C442 c443 C444 C445 C446 C447 C448 C500 C501 C502 C503 C504 C505 CR6 CR7 CR8 CR9 CR17 CRIB CR26 CR27 CR202 CR203 CR204 CR205 CR207 CR209 CR210 CR211 A3 Component Coordinates (1 of 2) X,Y C.3 C.3 C.3 C,3 D,2 D,2 D,2 0.2 [...]

Service Model 8904A CHANGES 2948A and above the +5VREF. Draw a jumper wire acrosse the opening and label it W1. Label the left end of the jumper, J8(2) and the right end of the jumper, J8(1). Draw node dot about 0.125 inch below J8(1) and label it, J8(3). Connect a common ground symbol to J8(3). Write the following note directly under the circuit b[...]

+ All 1 ow tSV0C I IVERVOLTAOE 'ROTECTION - OVERVOLTAGE RELAY DRIVE - - RELAY 7 DRIVER LOQlC 7 '5VUF ;q PM K11 P/O *ID2 I2 2 FLT Hl 1. 7( 7 -ATTENUATOR - 11113 b.UK 7 4, RII4 51.40 1 I -15voc R15+ 1.1w I I I I I FLOATINO OR ORWNDED AUDIO OUTPUT LIS2 rm OIll m I I I I ! I FLOATINO OR ORWNDED AUDIO OUTPUT I I ----.---A 7 OVERVOLTAGE DET[...]

Service Model 8904A ~ ~~ 2948A and above CHANGES A6 Schematic and Component locator 0 Use the component locator on page 8-60 for the A6 High Power output assembly component locations. 0 Use SS5 (Opt 006) on page 8-61 for the A6 High Power Oustput assembly schematic information. rev. 15DEC89 ss5 8-59[...]

Model 8904A ss5 8-60 Figure 8-1 7. Component Locator For S55 Service rev. 15DEC89[...]

PI0 A3/A10 OUTPUT ASSEMBLY 1 ! ------ I J480 I W18 I I I I I 35% I[...]