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Sony HB-75 Capacitor Replacement Guide

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Sony HB-75P inside
HB-75P with the upper cabinet off. The power board and its two block reservoir capacitors are at the rear; the main board electrolytics are spread across the lower board.

Sony's service manual for the HB-55P, HB-75P and HB-75B lists every capacitor in the European Sony HB-75, with part numbers, so the tables below are taken from it. The Japanese HB-75 runs on 100 V and is not covered by the manual; check its board against these lists before ordering.[1][2]

Which to replace first

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The capacitor failures reported on this model are on the two small regulator boards. One HB-75P arrived with the electrolytics on both boards burst, and the MSX Resource Center lists the model for failure-prone capacitors on small separate boards.[3][4] Replace those first, then the reservoir capacitors on the power board, then any main board electrolytic that shows leakage or a fault in the picture or sound.[5]

Power supply capacitors

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Fuse, power, +5 V and +12 V boards (parts list)[6]
Ref Board Value Voltage Sony part number Position
C1 Power 10,000 µF (block) 16 V 1-125-375-11 +5 V reservoir
C2 Power 3300 µF (block) 25 V 1-125-376-11 +12 V reservoir
C3 Power 330 µF 50 V 1-123-362-00 −12 V reservoir
C4 Power 47 µF 25 V 1-123-332-00 +5 V, after L1
C8 Power 47 µF 25 V 1-123-332-00 −12 V output
C5 Power 0.33 µF film 50 V 1-136-171-00 −12 V regulator input
C6 +5 V 47 µF 25 V 1-123-332-00 +5 V regulator output
C10 +5 V 0.33 µF film 50 V 1-136-171-00 +5 V regulator input
C7 +12 V 47 µF 25 V 1-123-332-00 +12 V regulator output
C11 +12 V 0.33 µF film 50 V 1-136-171-00 +12 V regulator input
C9 Fuse 4700 pF ceramic 400 V 1-161-953-00 Across the power switch; safety-critical

The positions are read from the supply schematic, which prints two ratings differently from the parts list: C3 as 35 V, and C4, C6, C7 and C8 as 16 V. Fit the higher rating.[7][6] C9 is a safety part and must be replaced with the same type.[6][8]

The regulator boards on the HB-75P photographed with burst capacitors are marked RE-19 (1-615-726-11) and RE-20 (1-615-727-11), while the manual lists the +5 V and +12 V boards as 1-613-624-11 and 1-613-625-11. Later production may differ, so read the values on your boards.[3][6]

Main board electrolytics

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Main board electrolytic capacitors (parts list)[9]
Ref Value Voltage Sony part number Fitted to
C1, C3, C5, C6, C7, C34, C44, C49, C54, C55, C59, C60, C68 47 µF 25 V 1-123-332-00 All three models
C66, C67 47 µF 25 V 1-123-332-00 HB-55P only
C4, C73 470 µF 6.3 V 1-123-298-00 All
C10 470 µF 10 V 1-123-310-00 All
C57 220 µF 10 V 1-123-308-00 All
C027 100 µF 10 V 1-123-307-00 All
C031 22 µF 25 V 1-123-330-00 All
C8, C9, C14, C018 10 µF 50 V 1-123-356-00 HB-75P and HB-75B only
C019 10 µF 50 V 1-123-356-00 All
C030, C41, C42, C45, C52, C61, C62, C63, C64 4.7 µF 63 V 1-123-369-00 All
C2, C022 0.47 µF 100 V 1-123-379-00 All

The parts list prints some designators with a leading zero (C016 to C035); they are given here as printed. The remaining main board capacitors are ceramic, film and Mylar parts.[9] C49 sets the power-on reset time together with R106.[10]

Procedure

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  1. Unplug the machine and open the case as described in the Sony HB-75 General Maintenance guide.
  2. Replace one capacitor at a time, matching value, at least the voltage rating, and polarity.[5]
  3. On the regulator boards, check the board and the regulator legs for electrolyte and corrosion after removing a burst capacitor.
  4. Clean any electrolyte off the boards and check the tracks near each capacitor.
  5. Reassemble, taping the loose function and cursor keytops if the keyboard comes out.[8]

After the recap

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Measure +5 V at pins 45 or 47, +12 V at pin 48 and −12 V at pin 50 of a cartridge slot, against pin 41.[11] Check that the machine starts into the Personal Data Bank and BASIC, and that the composite and RGB pictures are clean. If the colour or levels are wrong after work near the video circuits, the alignment figures are in the Sony HB-75 General Maintenance guide.[12]

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References

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  1. ↑ Sony, HB-55P/75P/75B Service Manual, PDF page 3 (printed pages 1-1 and 1-2), features and specifications: Z80A at 3.579545 MHz with one wait state in each M1 cycle; HB-75P/75B 64 KB RAM, HB-55P 16 KB; 48 KB ROM (MSX-BASIC 32 KB, utility program 16 KB); TMS9929ANL video; PAL composite video 1 V p-p, analogue RGB 0 to 0.7 V on the HB-75P/75B, RF on UHF channel 36; audio −5 dBs; 74 keys on the HB-75P/75B; cassette 1200/2400 baud; 14-pin printer port; two 9-pin joystick ports; two MSX cartridge slots; 220 V ±10 %, 50/60 Hz (HB-55P/75P) or 240 V ±10 %, 50/60 Hz (HB-75B); 24 W; about 405 × 67 × 245 mm and 3.5 kg. Hosted here as Sony HB-55P, HB-75P and HB-75B Service Manual.
  2. ↑ Category:Sony HB-75, MSX Resource Center wiki—link(accessed 2026-10-21) The HB-75 series: HB-75 (Japan, 100 V, one cartridge slot plus an expansion bus, RF and composite outputs, black or white, ¥69,800), HB-75AS (Australia, 240 V), HB-75B (UK, 240 V, £299), HB-75D (Germany, 220 V, QWERTZ), HB-75F (France, 220 V, AZERTY, RGB SCART only) and HB-75P (Europe, 220 V); the export models have two cartridge slots, RGB on SCART and composite video and audio on a 6-pin DIN; 1984; 64 KB RAM in slot 2, 16 KB VRAM; TMS9918ANL (HB-75) or TMS9929A (others); PSG AY-3-8910A or YM2149F; NEC D780C-1 Z80A; built-in Personal Databank; the Japanese HB-75 came with the HBI-55 data cartridge; links to Sony's HB-55P/75P/75B service manual on the MSX Archive.
  3. ↑ 3.0 3.1 Photograph posted to msx.pics on 25 March 2019 (https://www.msx.pics/image/Ud0TS), linked from the MSX Resource Center's vulnerable hardware page: "These capacitors had exploded on the Sony HB-75P when I got it", showing two small regulator boards marked RE-19 (1-615-726-11) and RE-20 (1-615-727-11) with replacement electrolytics and film capacitors marked 330nK beside each regulator.
  4. ↑ Vulnerable MSX hardware, MSX Resource Center wiki—link(accessed 2026-10-21) All MSX2 and later machines have a battery for the real-time clock; drained batteries, alkaline ones especially, leak; take removable batteries out before storage; lithium AA cells as an alternative. Lists the Sony HB-75P ("not as serious, as the problem caps are on separate small PCBs"), HB-F1II, HB-F1XD, HB-F1XDJ ("the ELNA caps are risky, the Nichicon ones are ok"), HB-F1XDmk2 and HB-F1XV among models with leaky capacitors. Fractured solder joints on DIN, RCA and DE-9 connectors cause flickering video and crackling sound; reflow them.
  5. ↑ 5.0 5.1 Recap recommendations, June 2018—link(accessed 2026-10-21) Reply by RetroTechie, 23 June 2018: in an MSX, the electrolytics used for supply bypassing round the board can often be removed without the machine stopping; those in the audio and video circuits show their condition in the output; those in the main power supply are worth replacing whatever their condition; compare the service manual's parts list with the board, and replace capacitors one at a time to avoid mixing up values or polarity; buy from established distributors. Wlcracks recommends Rubycon, Chemi-Con, Nichicon or Panasonic parts and checking the board for leakage and smell.
  6. ↑ 6.0 6.1 6.2 6.3 Sony, HB-55P/75P/75B Service Manual, PDF page 76 (printed 7-14), electrical parts list for the fuse, LED, power, +5 V and +12 V boards: C1 1-125-375-11 electrolytic (block) 10,000 µF 16 V; C2 1-125-376-11 electrolytic (block) 3300 µF 25 V; C3 1-123-362-00 electrolytic 330 µF 50 V; C4, C6, C7 and C8 1-123-332-00 electrolytic 47 µF 25 V; C5, C10 and C11 1-136-171-00 film 0.33 µF 50 V; C9 1-161-953-00 ceramic 0.0047 µF 400 V (safety-critical); F401 1-532-612-00 time-lag 160 mA; D1 to D4 10E2; D6 RB402; IC1 SI-3052V; IC2 SI-3122V; IC3 NJM79L12A; L1 22 µH micro inductor; LED D1 SLP171D; RF modulator 1-464-384-11 (55P/75P) or 1-464-383-11 (75B); +5 V board 1-613-624-11; +12 V board 1-613-625-11. Hosted here as Sony HB-55P, HB-75P and HB-75B Service Manual.
  7. ↑ Sony, HB-55P/75P/75B Service Manual, PDF pages 54 and 55 (printed 5-23 and 5-24), schematic of the fuse, LED, power, transformer, +5 V and +12 V boards: mains through fuse F401 (T160mA) and power switch S401, with C9 (4700 pF) across the switch, to transformer T401, which has a thermal fuse in its primary and taps for 220 V (AE) and 240 V (UK); +5 V from bridge D6 (RB-402), reservoir C1 (10,000 µF 16 V) and regulator IC1 (SI-3052V) on the +5 V board with C10 (0.33 µF) and C6 (47 µF 16 V), then L1 (22 µH) and C4 (47 µF 16 V); +12 V from D1 and D2 (10E-2), C2 (3300 µF 25 V) and IC2 (SI-3122V) on the +12 V board with C11 (0.33 µF) and C7 (47 µF 16 V); −12 V from D3 and D4 (10E-2), C3 (330 µF 35 V) and IC3 (NJM79L12) with C5 (0.33 µF) and C8 (47 µF 16 V); +5 V, +12 V and −12 V go to main board connector CN10; the power board also carries the RF unit and the 6-pin audio/video DIN socket. Hosted here as Sony HB-55P, HB-75P and HB-75B Service Manual.
  8. ↑ 8.0 8.1 Sony, HB-55P/75P/75B Service Manual, PDF pages 9 and 10 (printed 2-1 to 2-3): upper cabinet removal (three screws in the lower cabinet; unplug CN11 (13-pin) and CN12 (9-pin) on the main board and CN2 (2-pin) on the power board; release three hooks); main board removal (four heat sink screws, three main board screws, two screws in the blind plate, unplug CN10 (8-pin)); on the HB-75P/75B the function and cursor keytops are not locked in, so take the keyboard out and tape them before handling it; the BASIC ROM can be a single MSM38256-70RS mask ROM at IC42 with jumpers JW5 and JW7 to JW10 set to MASK and IC43 removed; the firmware ROM IC44 is an MSM38128A-77RS, with JW6 removed for an EPROM; parts marked with a warning triangle are safety-critical. Hosted here as Sony HB-55P, HB-75P and HB-75B Service Manual.
  9. ↑ 9.0 9.1 Sony, HB-55P/75P/75B Service Manual, PDF page 72 (printed 7-9), electrical parts list, main board (mounted board A-8050-098-A for the HB-75P/75B, A-8050-100-A for the HB-55P): electrolytics C1, C3, C5, C6, C7, C34, C44, C49, C54, C55, C59, C60 and C68 47 µF 25 V; C66 and C67 47 µF 25 V (HB-55P only); C2 and C022 0.47 µF 100 V; C4 and C73 470 µF 6.3 V; C8, C9, C14 and C018 10 µF 50 V (HB-75P/75B only); C019 10 µF 50 V; C10 470 µF 10 V; C027 100 µF 10 V; C030, C41, C42, C45, C52 and C61 to C64 4.7 µF 63 V; C031 22 µF 25 V; C57 220 µF 10 V. The list prints some designators with a leading zero (C016 to C035). Page 7-10 lists the remaining main board capacitors, all 0.01 µF ceramic. Hosted here as Sony HB-55P, HB-75P and HB-75B Service Manual.
  10. ↑ Sony, HB-55P/75P/75B Service Manual, PDF pages 13 and 14 (sections 3-2 and 3-3), theory of operation: at switch-on R106 and C49 hold pin 3 of IC26, a Schmitt-trigger inverter, low for several hundred milliseconds to reset the PPI (IC16) and the CPU (IC41); the firmware ROM (IC44) then sends PLL setting data to IC31, which starts the 4.43 MHz PAL subcarrier, before BASIC (IC42 and IC43) starts; slot 0 holds the ROMs, slot 1 is the top cartridge slot, slot 3 the rear cartridge slot, and on the HB-75 the 64 KB main RAM is in slot 2. The contents list (PDF page 2) gives section 3-5-3 as "Dynamic RAM (3764) (HB-75P/75B)" and the HB-55P's as the 4116. Hosted here as Sony HB-55P, HB-75P and HB-75B Service Manual.
  11. ↑ MSX Cartridge slot, MSX Resource Center wiki—link(accessed 2026-10-21) Pin-out of the MSX cartridge slot: pins 41 and 43 ground, 45 and 47 +5 V, 48 +12 V, 50 −12 V, 49 sound input, 42 CPU clock 3.579545 MHz; +5 V must supply up to 300 mA per slot and ±12 V up to 50 mA for all slots.
  12. ↑ Sony, HB-55P/75P/75B Service Manual, PDF pages 62 and 63 (printed 6-1 and 6-2), alignment, in this order: VCO phase, TP1 (junction of R37 and R38) 7.0 V ±0.1 V, set with VC1; subcarrier frequency, TP2 (junction of C28 and C47) 4.433618 MHz ±10 Hz, set with VC2; video output level, TP3 (pin 2 of CN1 on the power board) 1 V ±0.1 V p-p into 75 Ω, set with VR4; on the HB-75P/75B only, RGB levels 0.7 V ±0.1 V p-p into 75 Ω at TP4 (blue, pin 3 of CN3 or the collector of Q1, VR1), TP5 (red, pin 15 of CN3 or the collector of Q3, VR2) and TP6 (green, pin 11 of CN3 or the collector of Q5, VR3), with a white screen from COLOR 15,15. Hosted here as Sony HB-55P, HB-75P and HB-75B Service Manual.


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