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Sony HB-F700 Capacitor Replacement Guide

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Sony HB-F700S inside
HB-F700S with the cover off: a large black electrolytic on the power supply board at the left, and a row of five large electrolytics on the video board behind the rear sockets

Sony's electrical parts list for the Sony HB-F700 gives the value and voltage of every capacitor, so the list below is taken straight from the Sony HB-F700 Service Manual.[1] It covers the HB-F700P, F700S, F700F and F700D, which share the same capacitor list; the only capacitor marked for one model is a 56 pF ceramic, C49, on the HB-F700D, which also has line and noise filters (CF1 to CF13 and CF301 to CF304) that the other models lack.[1] The machine has 51 aluminium electrolytics and one tantalum capacitor.

Where the capacitors are

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Sony's designators run in series by circuit section:[1][2][3][4][5][6]

  • C901 to C919: the PS-133 power supply board, including the three reservoir capacitors.
  • C301 to C337: the DUS-135 video board on top of the chassis. Sony places IC301 (the V9938), the CPU clock trimmer CV301, the RGB presets RV301 to RV303 and the RGB socket CN309 on that board, and a photograph of an HB-F700S shows 300-series parts on the upper board.
  • C401 to C426: the drive section, numbered with its control chip IC401 (M51017AP).
  • C701 to C703: the mouse.
  • C1 to C53 and C501 to C510: not tied to a board in the list. Read the designators printed beside the capacitors on your own boards.

The parts list shows no electrolytic capacitors on the keyboard.[1]

Electrolytic capacitor list

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Power supply, PS-133 board (service manual, pages 40 and 77)
Ref Value Voltage Position
C909 22000 µF 16 V +5 V reservoir, after the bridge D904; a block electrolytic
C905 10000 µF 25 V +12 V reservoir, after D901 and D903
C912 470 µF 35 V −12 V reservoir, after D902
C904 100 µF 10 V +5 V output, IC902
C903 100 µF 16 V +12 V output, IC901
C907 100 µF 16 V −12 V output, IC903

[2][1]

DUS-135 video board, 300 series (service manual, pages 76 and 77)
Ref Value Voltage
C302, C313, C314, C315 100 µF 10 V
C312 220 µF 10 V
C325, C326, C327, C328, C329 470 µF 10 V
C317, C321, C330 47 µF 16 V
C309, C311, C318, C319, C320, C335, C337 4.7 µF 25 V
C336 1 µF 50 V
C310 0.47 µF 50 V

[1]

Drive section, 400 series (service manual, page 77)
Ref Value Voltage
C414 470 µF 16 V
C409 47 µF 16 V
C416 22 µF 50 V
C420 10 µF 25 V
C418 4.7 µF 35 V
C419 3.3 µF 50 V
C415 2.2 µF 50 V
C421, C422, C423, C424, C426 0.47 µF 50 V

[1]

Other electrolytics (service manual, pages 76 and 77)
Ref Value Voltage Section
C31, C43 33 µF 6.3 V Main series
C41 10 µF 16 V Main series
C29 4.7 µF 25 V Main series
C52 1 µF 50 V Main series
C501, C506 47 µF 6.3 V 500 series
C503, C508 4.7 µF 25 V 500 series
C702, C703 47 µF 6.3 V Mouse
C701 2.2 µF tantalum not given Mouse

[1][4]

Notes on the list:[1]

  • C409 and C414 are printed with the same Sony part number, 9-989-170-01, but with values of 47 µF and 470 µF. Read the value on the part before ordering.
  • C909 is described as a block electrolytic. Measure its diameter, height and lead spacing before buying a replacement.
  • Several small parts are rated at 6.3 V (C31, C43, C501, C506, C702 and C703). Replacements must be rated at 6.3 V or more.

Which to replace first

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Advice on the MSX Resource Center forum is to treat the main power supply's capacitors as worth replacing whatever their condition, to judge audio and video capacitors by the output, and to leave small decoupling capacitors unless there is a reason.[7] Members advising an HB-F700F owner said to replace any electrolytic that is swollen or even slightly concave on top, and to replace the power supply capacitors too.[8] On the HB-F700 that means:

  1. C909, C905 and C912, the three reservoirs, and the output capacitors C904, C903 and C907.
  2. The five 470 µF capacitors C325 to C329 and the other large parts on the video board, if the picture is poor.
  3. The drive section capacitors, if the drive misbehaves.
  4. The rest only if they show leakage or bulging.

A recap did not cure the HB-F700F in that thread, which stayed dead with every capacitor replaced, so check the supply rails and the clock first on a dead machine.[8]

Procedure

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  1. Unplug the machine and open it as described in the Sony HB-F700 General Maintenance guide. Take the DUS-135 board out for work on it; take the bottom plate off for the main board.[9]
  2. Photograph each board before starting, so that every polarity mark can be checked afterwards.
  3. Replace one capacitor at a time, matching the stripe to the original.[7]
  4. The video board is not glass-epoxy and cracks easily. Support it and use as little heat as possible.[10]
  5. Inspect the Ni-Cd backup battery BT1 while the boards are out. Remove it at once if it has leaked.[11][8]
  6. Clean off old flux and any electrolyte, check the tracks round the large capacitors, and refit.

After the recap

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Measure the regulator outputs: 5 V at IC902 pin 2, 12 V at IC901 pin 2 and −12 V at IC903 pin 1.[2] Check the 9 V output of IC307 on the video board.[10] Then check that MSX-BASIC starts, that the drive reads a disk, and that the RGB picture and the sound are clean. Faults that remain are covered in the Sony HB-F700 Troubleshooting Guide.

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References

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  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Sony, Service Manual HB-F700P/F700S/F700F/F700D, pages 76 and 77, section 8, "Electrical Parts List". See Sony HB-F700 Service Manual. Electrolytics (described "ELECT", Sony part numbers in the 1-123, 1-124, 1-125 and 9-9xx series): C29 4.7 µF 25 V; C31 33 µF 6.3 V; C41 10 µF 16 V; C43 33 µF 6.3 V; C52 1 µF 50 V; C302 100 µF 10 V; C309 4.7 µF 25 V; C310 0.47 µF 50 V; C311 4.7 µF 25 V; C312 220 µF 10 V; C313, C314, C315 100 µF 10 V; C317 47 µF 16 V; C318, C319, C320 4.7 µF 25 V; C321 47 µF 16 V; C325 to C329 470 µF 10 V; C330 47 µF 16 V; C335 4.7 µF 25 V; C336 1 µF 50 V; C337 4.7 µF 25 V; C409 47 µF 16 V; C414 470 µF 16 V; C415 2.2 µF 50 V; C416 22 µF 50 V; C418 4.7 µF 35 V; C419 3.3 µF 50 V; C420 10 µF 25 V; C421 to C424 and C426 0.47 µF 50 V; C501 47 µF 6.3 V; C503 4.7 µF 25 V; C506 47 µF 6.3 V; C508 4.7 µF 25 V; C702 and C703 47 µF 6.3 V; C903 100 µF 16 V; C904 100 µF 10 V; C905 10000 µF 25 V; C907 100 µF 16 V; C909 22000 µF 16 V, "ELECT (BLOCK)"; C912 470 µF 35 V. Tantalum: C701 2.2 µF, no voltage given. C409 and C414 are printed with the same part number, 9-989-170-01, but different values (47 and 470). C49 1-101-884-00, ceramic 56 pF 50 V, HB-F700D only; CF1 to CF13 line filters and CF4, CF301 to CF304 noise filters, HB-F700D only.
  2. ↑ 2.0 2.1 2.2 Sony, Service Manual HB-F700P/F700S/F700F/F700D, page 40, schematic diagram, PS-133 board. See Sony HB-F700 Service Manual and File:Sony HB-F700 PS-133 power supply schematic.png. Transformer T901; primary through the power switch, fuse F901 and line coil L901, with C911 and C915 (0.022 µF 250 V) and C906 (2200 pF 400 V). +5 V: bridge D904 (D5FB20F), reservoir C909 22000 µF 16 V, regulator IC902 SI3052V (input pin 3, 9.3 V marked; ground pin 1; output pin 2, 5 V), output capacitor C904 100 µF 10 V, C902 0.33 µF. +12 V: D901 and D903 (U05G), reservoir C905 10000 µF 25 V, IC901 SI3122V (input pin 3, 18.2 V marked; ground pin 1; output pin 2, 12 V), C903 100 µF 16 V, C901 0.33 µF. −12 V: D902 (10E2N), reservoir C912 470 µF 35 V, IC903 NJM79L12A (input pin 2, 19.1 marked; ground pin 3; output pin 1, −12), C907 100 µF 16 V, C908 0.33 µF. Power LED D905 (TLG124A) on the LE-50 board.
  3. ↑ Sony, Service Manual HB-F700P/F700S/F700F/F700D, pages 25 and 26, section 5, "Adjustments". See Sony HB-F700 Service Manual. BASIC adjusting program headed "CHECK PROGRAM for HB-F5/F500": W key, white screen for the RGB level adjustment; S key sets the timer clock output (lines 200 and 210: OUT &HB4,14:OUT &HB5,0 and OUT &HB4,15:OUT &HB5,8); R key cancels it (line 240: OUT &HB5,12). Connect a KX-14CP1 monitor to CN309 or terminate pins 6, 7 and 8 of CN309 in 75 ohms. CPU clock: IC301 pin 8 on the DUS-135 board, 3,579,540 to 3,579,549 Hz, adjust CV301. Timer clock: 100 kΩ pull-up from TP4 to +5 V, TP4 on the PU-53 board, 15.9999 to 16.0001 Hz, adjust CV1. RGB levels: 0.7 ± 0.02 V from sync level to colour level at CN309 pin 6 (red, RV302), pin 7 (green, RV303) and pin 8 (blue, RV301). Floppy controller, three minutes after switch-on with TP1 grounded by a jumper: VCO frequency 250 ± 1 kHz at TP3, adjust RV2; read pulse width 0.5 µs ± 10 ns at TP2, adjust RV1; remove the jumper afterwards.
  4. ↑ 4.0 4.1 Sony, Service Manual HB-F700P/F700S/F700F/F700D, pages 29 to 32, mounting and schematic diagrams, mouse section. See Sony HB-F700 Service Manual. Mouse board with IC701 LA6339M comparator and IC702 MB88201 controller; C702 and C703 47 µF 6.3 V.
  5. ↑ Sony, Service Manual HB-F700P/F700S/F700F/F700D, pages 53 to 58, mounting and schematic diagrams, drive section. See Sony HB-F700 Service Manual. Drive section built round IC401 (M51017AP, floppy drive control and read/write), with the stepping motor M401 and photo interrupters PH401 and PH402.
  6. ↑ File:Sony HB-F700S inside.jpg, photograph of an HB-F700S with the top cover off, uploaded to the MSX Resource Center wiki by Gdx on 15 April 2016. Read from it: the transformer at the front left; the power supply board behind it with a fuse, a D5FB20 bridge and a large reservoir capacitor, under a heatsink along the back panel; the upper board with the V9938, a row of five large electrolytic capacitors behind the rear DIN sockets, resistors R352 to R355 and three blue presets in front of them, and a relay at the back right.
  7. ↑ 7.0 7.1 Recap recommendations, June 2018—link(accessed 2026-10-21) Reply by RetroTechie, 23 June 2018: in an MSX, electrolytics used for supply bypassing can often be removed without the machine stopping, those in the audio and video circuits show their condition in the output, and those in the main power supply are worth replacing whatever their condition; use the service manual's parts list, compare it with the board, and replace one capacitor at a time.
  8. ↑ 8.0 8.1 8.2 Diagnostic on dead Sony HB-F700F, 2015–2017—link(accessed 2026-10-21) Thread by Louthrax about an HB-F700F that showed nothing and gave no Caps Lock response. gdx, 1 March 2015: failed electrolytics are often swollen on top, replace any that is even slightly concave; old solder joints age badly, resolder them with flux; "The VDP of HB-700 doesn't like" a cartridge inserted with the power on. RetroTechie, 2 March 2015: no Caps Lock response usually means the CPU gets no clock (a dead VDP can cause that) or something stops the Z80, ROM or RAM; test with a known good RAM cartridge and a cartridge that plays sound at power-on, with a speaker on the audio output. l_oliveira, 3 March 2015: check power, then clocks, then the tracks, then the VDP, ROM, RAM and CPU; a VRAM fault spoils the picture but does not stop the machine starting. Louthrax, 28 October 2016: the top board had been recapped without effect; the backup battery had started to leak and was removed and the tracks cleaned; he describes it as a sealed Ni-Cd battery, 50 mAh, 2.4 V. sd_snatcher, 28 October and 6 November 2016: a battery fault stopped an NMS 8245 booting; the main ROM is IC5, a 32 KB 28-pin part that can be socketed and replaced with an MSX1 BIOS for a test. l_oliveira, 6 November 2016: a dead battery will not stop the machine booting unless the clock's power circuit is faulty. Eugeny_Brychkov, 6 November 2016: with a multimeter, measure the voltage on the CPU's pin 26 (reset) and pin 6 (clock) with the machine switched on. gdx, 8 November 2016: a turbo R would not boot with drained batteries; replace a rechargeable cell with the same type (Ni-Cd) and fit it in a holder rather than soldering to it. Louthrax, 15 June 2017: all motherboard capacitors changed and the board still dead; it was passed to another member for repair.
  9. ↑ Sony, Service Manual HB-F700P/F700S/F700F/F700D, pages 21 and 22, section 4, "Disassembly". See Sony HB-F700 Service Manual. Starting from "remove the case": cartridge holder (two BVTT 3 × 8 screws, the holder, then the EX-119 board); DUS board (BVTT 3 × 6 screws, then the board); front panel (BVTT 3 × 6 screws, the connector cover, then the front panel assembly); main board (loosen the BVTT 3 × 6 screws, remove the bottom plate, then the BVTT 3 × 6 screws and the main board); floppy drive unit (BVTT 3 × 6 screw, pull up the connectors, lift the unit out). Pages 23 and 24 cover the drive motor and head block.
  10. ↑ 10.0 10.1 Sony HB-F700S with problems, March 2016—link(accessed 2026-10-21) Thread by Pablibiris about an HB-F700S with no picture. RetroTechie, 13 March 2016: IC307 (78M09) near the RGB connector should have about 12 V on its input pin, ground on the middle pin and about 9 V on its output, which feeds the R, G, B and sync output circuits; if the 9 V fails, RGB and A/V output are lost. Pablibiris, 14 March 2016: two boards, an upper one with the RGB and tape connections and a lower motherboard; replacing IC307 brought the picture back, after which graphics were corrupted and the boot screen reported 64 KB of VRAM. Wierzbowsky, 15 March 2016: most MSX2 machines have 128 KB of VRAM, so a 64 KB report points to the VRAM chips or their connection to the VDP; trace CAS0 and CAS1 from the VDP to the pairs of VRAM chips. Pablibiris, 15 March 2016: photographs of a strange cursor and garbled characters and graphics; the TESTRAM program passed the RAM but restarted the machine during the VRAM test; changing all the memory did not help; fitting a complete replacement video board did, and he suggests the VDP may have been broken. Jipe, 15 March 2016: check the solder joints on the VRAM; the board in the HB-700 breaks easily because it is not epoxy.
  11. ↑ Sony, Service Manual HB-F700P/F700S/F700F/F700D, pages 76 to 80, section 8, "Electrical Parts List". See Sony HB-F700 Service Manual. Boards PU-53 (PR-53 on the F and S models), DUS-135, CN-149, CN-150, CN-151, PS-133, LE-50 and EX-119; BT1 1-528-171-11, battery, storage, Ni-Cd (GB50H); IC307 NJM78M09A; IC901 SI3122V; IC902 SI3052V; IC903 NJM79L12A; F901 fuse T630 mA (1-532-284-11, marked as safety-critical); S901 push switch (AC power); T901 power transformer 1-448-626-11.


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