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Sony HB-F1XDJ General Maintenance

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Sony HB-F1XDJ main board
HB-F1XDJ main board. The HIC-1 module stands at the rear right and the CR2032 that backs the MSX-JE dictionary is soldered at the right.

Sony published no maintenance schedule for the Sony HB-F1XDJ, and no service manual for it has been found. The steps here come from an owner's maintenance notes, repair reports on the MSX Resource Center forum, and Sony's service guide for the related HB-F1XD. The HB-F1XV uses the same main board, so most of it applies to that machine too; its own notes are in the Sony HB-F1XV General Maintenance guide.[1][2]

Safety

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The HB-F1XDJ has its mains transformer inside the case and runs on AC 100 V, 50/60 Hz.[3] Mains voltage is present on the left-hand side of the case with the lid off, so unplug the lead before opening it.[1] Where the mains supply is 220 to 240 V, run the machine through a step-down transformer rated for at least its 31 W.

Opening the case

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The sequence below is from an owner who has had the main board out of his HB-F1XDJ several times.[1]

  1. Unplug the mains lead.
  2. Remove the five screws on the underside and the screw at the video output connector.
  3. Lift the top cover gently. Three cables run from it to the main board, for the lamps and the speed controller and Ren-Sha Turbo sliders; unplug them before taking the cover away.
  4. Unplug the keyboard's film cable from the main board and lift the keyboard out.
  5. Remove the metal shield under the keyboard.
  6. Unplug the drive's signal and power cables, remove the four screws at the corners of the drive bracket, and lift the drive out on its bracket.
  7. Remove the aluminium heat sink (three screws). Keep the insulating sheet under the FET.
  8. Unplug the cable from the transformer and the cable from the battery holder at the left-hand side.
  9. Remove the screws holding the main board and lift it out, easing it past the joystick connectors and the transformer.

The main board needs careful handling. The same owner found that the jumper wires on the solder side come away easily, that bending the board or knocking it cracks solder joints, that the copper lifts more easily than on a new board, and that the blue film lines on the solder side are traces too.[1]

When refitting the top cover, route the three cables from the lamp and slider housing into the space between the drive and the top of the keyboard, not over the drive, or the cover will not close flush.[4]

Batteries

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Clock cells

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The calendar clock runs from two AA cells in a holder at the left-hand side, connected to the main board by a cable.[1] Alkaline cells leak when they go flat, and the leakage corrodes whatever it reaches. The owner's notes recommend zinc-carbon (manganese) cells and accept alkaline cells only if they are watched; the MSX Resource Center recommends lithium AA cells or Eneloop rechargeables and advises against alkaline.[1][5] Take the cells out before the machine goes into storage.[6] If a cell has already leaked, clean the holder and the cable as described in Battery Explosion, Capacitor or Corrosion Damage.

MSX-JE dictionary cell

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A tabbed CR2032 lithium cell, soldered to the main board under the keyboard, keeps the SRAM that holds the MSX-JE kanji conversion dictionary. When it is flat the dictionary is cleared at every switch-on.[1] To replace it:

  1. Take the main board out as above.
  2. Desolder the old cell from the solder side quickly; a tabbed lithium cell that is overheated can burst.
  3. Fit a CR2032 holder in its place, and fix the holder down with double-sided tape so that it cannot lift and touch the shield above it.
  4. Fit a new CR2032.

Never solder leads directly to an untabbed coin cell; the heat can make it catch fire or burst.[1] One repairer simply removed a flat cell and fitted nothing in its place, which loses the dictionary's contents at power-off.[7][1]

Floppy drive

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The drive is a Mitsumi D357B, a 720 KB 3.5-inch unit driven by a rubber belt.[1] With age the belt stretches, and in damp storage it can soften and melt onto the pulleys. The drive then fails to read: a disk in the drive is ignored at start-up, BASIC comes up, and FILES returns "Disk offline".[1] A replacement belt is 59 mm in diameter, 186 mm long, 2.8 mm wide and 0.4 mm thick.[5] General drive work is covered in Floppy Drive Repair.

The drive takes +5 V only and uses a standard 34-pin signal connector with pin 1 on the left, so a 720 KB drive without a VFO that runs on +5 V alone, or a floppy emulator, can replace it. Watch the connector orientation: a reversed cable leaves the drive lamp on and makes the head chatter. The grey bezel on the top cover is shaped for the Mitsumi drive and usually has to come off with another drive.[1]

Keyboard and controls

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The keyboard is a membrane on plastic film. Liquid that gets in between the keys corrodes the printed traces, and the affected keys stop working; the damaged trace shows as a darker patch on the film.[1][8] The keyboard is held together with screws. A broken trace can be repaired by scraping back the thin coating, bridging the gap with conductive silver ink for circuit boards, and sealing the repair once the ink has cured and the trace tests continuous.[1]

The joystick ports are gold-plated but still pick up dirt and give poor contact; clean them with contact cleaner before suspecting the board.[1]

Capacitors

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The machine has two groups of capacitors known to leak: three surface-mount electrolytics on the HIC-1 video and audio module, and ELNA-brand electrolytics on the main board.[4][7] Electrolyte from either group corrodes the board around it. Inspect both groups whenever the case is open. Forum members advise replacing them before they leak, because repairing corroded traces is far more work.[7] Values, positions and the procedure are in the Sony HB-F1XDJ Capacitor Replacement Guide.

The owner's notes add that parts of the board use quaternary-salt electrolytics, which leak and break traces when the machine is kept unpowered in a damp cupboard or shed. They recommend storing it in a dry, ventilated room.[1]

Connectors

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Repeated plugging cracks the solder joints on the DIN, RCA and joystick connectors, which shows as flickering video or crackling sound when the lead is moved. Reflow the joints with fresh solder.[6]

Checklist

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  1. Remove the AA clock cells if the machine is going into storage, or check them for leakage.
  2. Open the case and look at the HIC-1 module and the ELNA capacitors on the main board for leakage or corrosion.
  3. Check the CR2032: if the MSX-JE dictionary is lost at each start, replace it.
  4. Check the drive belt, and replace it if it is slack or sticky.
  5. Test every key and both joystick ports.
  6. Move each video and audio lead while watching and listening for faults.

For fault-finding see the Sony HB-F1XDJ Troubleshooting Guide.

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References

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  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 8ビットパソコン HB-F1XDJ (MSX2+) ネタ, 25 October 2016—link(accessed 2026-10-21) In Japanese. An owner's notes on the HB-F1XDJ, which he says apply to the HB-F1XV because its hardware is the same: kanji dictionary SRAM backed by a tabbed Sony CR2032 soldered to the main board under the keyboard, which clears the dictionary at every start when flat; calendar and clock backed by two AA dry cells, manganese cells recommended, alkaline cells acceptable but watch for leaks; Mitsumi D357B 720 KB drive without VFO, with a rubber belt that stretches or melts; floppy drive powered by +5 V only, 34-pin signal connector, pin 1 on the left; AC 100 V present at the left-hand side of the case; disassembly sequence; old jumper wires on the main board come away easily and the board's joints and traces are fragile; some lots lose FM volume, cured by replacing C99, a 50 V 1 µF electrolytic in the YM2413 block on the left of the main board; quaternary-salt electrolytics used in places, which leak and break traces when the machine is stored unpowered in damp places; match the height of replacement capacitors; keyboard film traces corroded by spilled liquid, repaired with conductive silver ink; joystick ports gold-plated but prone to dirty contacts; a start-up password can be set and is cleared by holding GRAPH and STOP while switching on; after a drive swap, a reversed signal cable leaves the drive lamp lit and makes the head chatter, and a drive that is not recognised gives "Disk Offline".
  2. ↑ File:Sony HB-F1XV main board.jpg, photograph of an HB-F1XV main board uploaded to the MSX Resource Center wiki by Gdx on 4 April 2016. Read from it: the same layout as the HB-F1XDJ board, with "MSX2+SYSTEM" and "AUDIO & VIDEO" printed on it, the large reservoir capacitor at top left, the HIC-1 module at the rear right, the coin cell at the right, and a trimmer marked CV2 beside test point TP1 near the front right.
  3. ↑ Rating label of the HB-F1XDJ, photographed for the MSX Resource Center wiki (File:Sony HB-F1XDJ rating label.jpg, uploaded by Mars2000you, 18 January 2023): "MODEL HB-F1XDJ PERSONAL COMPUTER 100V 31W 50/60Hz", ソニー株式会社, Made in Japan.
  4. ↑ 4.0 4.1 Urgent alert to MSX2/2+ owners: suicide capacitors on HIC-1 daughterboard, July 2015 onwards—link(accessed 2026-10-21) Opening post by sd_snatcher, 19 July 2015: the HIC-1 (EMC-NX0039) module in the Sony HB-F1XV, HB-F1XDJ, HB-F1XDmkII and HB-F1XD and the Panasonic FS-A1, FS-A1mkII and FS-A1F carries three SMD aluminium electrolytics that leak and damage the board: C10 10 µF 16 V, C14 10 µF 16 V and C22 100 µF 16 V, C22 the worst; ceramic or tantalum replacements in 3216 (10 µF) and 4532 or 6032 (100 µF) sizes, rated 16 V or more. Reply by jltursan: two HB-F1XD and one HB-F1XV affected, the first symptom usually lower sound volume. Reply by RetroTechie: cut through the solder or use two irons to lift the old parts without heating the board. Reply by dublevay, 5 September 2020, on an HB-F1XV: the original 100 µF part was a 6.3 V type marked 6A and the 10 µF parts were 16 V; hot air blew three small resistors (820 Ω, 1 kΩ and 0 Ω) off the module, which he refitted; he fitted Kemet tantalums first; the band on a tantalum marks its positive end, unlike an aluminium electrolytic, which marks the negative; after fitting tantalums, then Panasonic HD (10 µF, 16 V) and HC (100 µF, 6.3 V as original) SMD electrolytics chosen to match the original sizes, there was still no composite or RF picture until the 22 µH inductor (marked 220) below the lower 10 µF capacitor, which had a bad joint, was reflowed; RGB worked throughout. Reply by Louthrax, 23 December 2025, on reassembling an HB-F1XDJ: the three cables from the lamp and slider housing go in the space between the drive and the top of the keyboard, not on top of the drive.
  5. ↑ 5.0 5.1 Sony HB-F1XDJ, MSX Resource Center wiki—link(accessed 2026-10-21) Community specification and maintenance page: MSX2+, released 1988-10-21 at ¥69,800; S1985 MSX-Engine, V9958, YM2413; 720 KB drive; AC 100 V ±10 %, 50/60 Hz. Maintenance notes: drive belt 59 mm in diameter, 186 mm long, 2.8 mm wide and 0.4 mm thick; HIC-1 daughterboard with three SMD electrolytics that leak; ELNA capacitors on the system board that leak; FM crackle fix (replace C99 with a wire and C20 with a non-polarised capacitor of the same value, after Niga); lithium AA or Eneloop cells recommended for the clock, alkaline cells advised against; link to a keyboard repair kit for the HB-F1XD, XDJ and XV sold by classicpc.org.
  6. ↑ 6.0 6.1 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 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.
  7. ↑ 7.0 7.1 7.2 Sony HB-F1XDJ capacitor leakage repair guide, 21 December 2017—link(accessed 2026-10-21) Repair report by Omega: an HB-F1XDJ that sometimes would not start, was unstable when it did, and produced wrong key presses (EF for E). Electrolyte had leaked round the HIC module and from through-hole capacitors on the main board, through to the solder side; all four ELNA 47 µF capacitors (6.3 V, per his later correction) had leaked and lost their capacitance. He desoldered the SMD capacitors with hot air, cleaned with isopropyl alcohol, neutralised with vinegar, scraped the pads, used SMD flux and fitted Panasonic parts, replaced every ELNA electrolytic on the board, left the Nichicon ones, and removed the flat CR2032. The capacitors on the HIC module served only the RGB to composite circuit; RGB passes through the module unaffected. Some copper was corroded but no traces needed repair, and the machine then started every time and the keyboard worked. He advises HB-F1XDJ owners to check for leakage and have the ELNA capacitors replaced preventively, because broken traces mean labour-intensive repairs. Reply by Wierzbowsky, 7 January 2018, on an HB-F1XV: replaced the three daughterboard capacitors with 10 µF 16 V size B and 100 µF 16 V size D tantalums before any leak, and replaced the soldered cell, which he calls the clock battery, with a socket for a CR2032.
  8. ↑ MSX2+, Japanese Wikipedia—link(accessed 2026-10-21) In Japanese. The HB-F1XDJ was released on 21 October 1988; its case was carried over from the MSX2 HB-F1XD series; MSX-JE built in. After about a year of use the FM sound on the HB-F1XDJ became quieter because of a circuit fault, which Sony dealt with by replacing a capacitor. Across the series, dirt getting in between the keys breaks the traces on the keyboard film. The HB-F1XV changed the colouring and expanded the bundled software.


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