Sony HB-F1 Capacitor Replacement Guide
No parts list, schematic or capacitor list for the Sony HB-F1 has been found, so the values have to be read from the board itself. What is known is below, with a method for recording your own board.
What is known
[edit | edit source]- Four large electrolytic capacitors stand at the rear left of the main board, beside the aluminium heat sink, with smaller electrolytics round them and across the left half of the board. Their values cannot be read in the published photograph.[1]
- The machine is powered by an external adapter giving DC 9 V and AC 18 V; regulation is on the main board, with two +5 V regulators and a 12 V regulator.[2][3]
- The EX-1 daughterboard carries a single ceramic capacitor and nothing that can leak.[3]
- The HB-F1 has no HIC-1 module, so the three leak-prone surface-mount capacitors of the HB-F1XD family are not fitted.[4][3] The MSX Resource Center's list of hardware with leak-prone capacitors does not name the HB-F1.[5]
Which to replace first
[edit | edit source]Advice on the MSX Resource Center forum for MSX machines generally is to replace the main power supply's capacitors whatever their condition, to judge the audio and video capacitors by the picture and sound, and to leave the small supply bypass capacitors unless there is a reason. The same advice recommends Rubycon, Chemi-Con, Nichicon or Panasonic parts from established distributors.[6] On the HB-F1 that means:
- The four large capacitors at the rear left and the electrolytics round the regulators.
- Any capacitor in the audio and video area, if the picture or sound is poor.
- Any capacitor showing leakage, bulging or corrosion round its leads.
Recording the board
[edit | edit source]- Unplug the adapter, open the case and lift out the keyboard.
- Photograph the whole board, then each electrolytic close up so that the printing on the sleeve can be read.
- For each one, note the designator, value, voltage, brand, diameter and height, and which side the stripe faces.
- Order replacements of the same value, at least the same voltage, and a size that fits the space.
| Ref | Value | Voltage | Brand | Diameter × height | Notes |
|---|---|---|---|---|---|
Procedure
[edit | edit source]- Replace one capacitor at a time, with the stripe on the same side as the original; working one at a time avoids mixing up values and polarity.[6]
- Clean any electrolyte off the board and check the tracks near each capacitor for corrosion.
- Refit the keyboard and close the case.
After the recap
[edit | edit source]Check both adapter outputs, then 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.[7] Check that BASIC starts, that both cartridge slots work, and that the picture and sound are clean. Remaining faults are covered in the Sony HB-F1 Troubleshooting Guide.
Related pages
[edit | edit source]- Sony HB-F1
- Sony HB-F1 General Maintenance
- Sony HB-F1 Troubleshooting Guide
- Capacitor Failure Symptoms
References
[edit | edit source]- ↑ File:Sony HB-F1 main board.jpg, photograph of an HB-F1 main board uploaded to the MSX Resource Center wiki by Mars2000you on 13 June 2023. Read from it: "MSX2SYSTEM" printed on the board; four large electrolytic capacitors at the rear left beside an aluminium heat sink, with smaller electrolytics round them; an Omron relay at the rear; a small daughterboard marked EX-1 at the centre; Sharp LH0080A (Z80A) CPU; Yamaha S1985 MSX-Engine with a crystal and a blue trimmer marked TIMER beside it; Fujitsu MB81464-12 DRAMs; the cartridge slot connectors at the right.
- ↑ Sony AC-HB3, MSX Resource Center wiki—link(accessed 2026-10-21) The external power supply supplied with the Japanese HB-F1 and HB-F1II: input AC 100 V, 50/60 Hz, 23 VA; outputs DC 9 V 1.2 A and AC 18 V 170 mA; connector sometimes called Mini-IEC; same specification, connector and pin-out as the Panasonic FS-AA51, so the two are interchangeable; the Sony AC-HB1 series and AC-HB2P use a different connector and voltages and cannot be substituted. The page shows a circuit diagram of the adapter.
- ↑ 3.0 3.1 3.2 Trying to repair a Sony HB-F1 (MSX 2), December 2017—link(accessed 2026-10-21) Apocalypse, a console and arcade board repairer, on an HB-F1 with a black screen and the power lamp lit: the main ROM IC14, a Fujitsu MB831124 128K × 8 mask ROM in a 28-pin package, was dead; rails were correct from two +5 V regulators and a 12 V regulator; clock present, reset not stuck, activity on the buses; the EX-1 daughterboard carries only one ceramic capacitor; a Philips diagnostic ROM reported error 711 (RTC); the clock chip is inside the S1985; he fitted sockets and new Z80 and 41464 RAM chips without curing it, and the thread ends unresolved. Replies: the machine has a single mask ROM; gdx suggests a 64 KB EPROM such as a W27C512 holding only the main ROM and sub-ROM; sd_snatcher suggests a RAM cartridge in a slot to boot past faulty internal RAM, and an MSX1 BIOS to test the CPU, RAM and slot selection; with the speed controller slider disconnected the machine boots very slowly, and a jumper across its connector restores normal speed; meits: the machine makes no sound at start-up unless a game cartridge is fitted, and starts without the keyboard but then sits in the built-in software; Jipe first suggested the HIC-1, then corrected himself that the HB-F1 uses a different board; gdx: the AA batteries are not needed to start, but bad values in the clock chip can stop it starting, so replace weak batteries or take them out; gdx: check /ALM on pin 87 of the S1985 and the clock crystal pins.
- ↑ MSX2以降用ハイブリッドIC「EMC-NX0039」の回路図, 19 May 2020—link(accessed 2026-10-21) In Japanese, with the author's redrawn schematic as a PDF. Mitsumi hybrid IC EMC-NX0039 (HIC-1): RGB to NTSC encoder (CXA1145M), sound output amplifier mixing the PSG, the 1-bit sound port and the audio from slots 1 and 2, reset and pause muting, cassette interface amplifiers and relay control. Used in the Sony HB-F1II, HB-F1XD, HB-F1XDmk2, HB-F1XDJ and HB-F1XV and the Panasonic FS-A1mkII and FS-A1F. Sony part number 1-464-877-11. Two 10 µF and one 100 µF electrolytics, all known to leak; the author replaced them with tantalums and advises fused types because tantalums fail short. C26 is a through-hole part on early modules and an SMD part on later ones. R32 and R33 are 220 kΩ on Sony modules and 150 kΩ on Panasonic ones.
- ↑ 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.
- ↑ 6.0 6.1 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.
- ↑ 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.