Toshiba HX-10
 | |
| HX-10 (64K) with the HX-E600 slot expander behind it | |
| Specifications | |
|---|---|
| Manufacturer | Toshiba |
| Type | MSX1 home computer |
| Released | 1983 (Japan), 1984 (Europe)[1] |
| Intro price | £279 (UK, 1984)[2] |
| CPU | Z80A at 3.58 MHz[3] |
| Memory | 64 KB RAM (16 KB on the HX-10S and HX-10SA), 16 KB VRAM, 32 KB ROM[3][1] |
| Storage | Cassette, cartridges[3] |
| Display | TMS9929A (European models); TMS9918A or TMS9928A (Japanese models)[1][3] |
| Sound | AY-3-8910[3] |
| Power | Internal transformer; 240 V AC, 50 Hz, 17 W (UK model)[3] |
| Dimensions | 370 × 60 × 245 mm[3] |
| Weight | 2.8 kg[3] |
| OS / Firmware | MSX BASIC in ROM[3] |
| Model no. | HX-10 series (HX-10S, D, SA, DP, DPN in Japan; HX-10AA, E, F, I, P, SF in Europe) |
The Toshiba HX-10 is Toshiba's best-known MSX1 computer. It was launched in Japan in 1983 as part of the Pasopia IQ range and adapted for several European countries in 1984.[1] Toshiba was the first maker to offer an MSX with 64 KB of RAM; the early Japanese HX-10S and HX-10SA have 16 KB, every other version 64 KB.[1] All versions have one cartridge slot and an expansion bus at the back for the HX-E600 slot expander, and the keyboard has blue cursor keys, a red STOP key and a green GRAPH key.[1] In Britain the machine is the HX-10P, labelled simply HX-10, which cost £279 in late 1984 and was later sold in a starter kit with a data recorder and software.[2]
Specifications
[edit | edit source]| Item | Figure |
|---|---|
| Processor | Z80A at 3.58 MHz (Sharp LH0080A) |
| Memory | 64 KB RAM, 32 KB ROM, 16 KB video RAM |
| Video | TMS9929A; RF and composite video outputs |
| Sound | AY-3-8910; audio output |
| Keyboard | 73 keys |
| Cassette | FSK, 1200 or 2400 baud |
| Printer | Centronics parallel |
| Expansion | Cartridge bus and expansion bus; two joystick ports |
| Power | 240 V AC, 50 Hz, 17 W |
| Size and weight | 370 × 60 × 245 mm, 2.8 kg |
Versions
[edit | edit source]| Model | Market | RAM | Notes |
|---|---|---|---|
| HX-10S | Japan | 16 KB | First revision, separate ICs, no printer port |
| HX-10D | Japan | 64 KB | First revision, separate ICs, no printer port |
| HX-10SA | Japan | 16 KB | Second revision, probably never sold |
| HX-10DP | Japan | 64 KB | Second revision, printer port |
| HX-10DPN | Japan | 64 KB | RGB output, printer port |
| HX-10AA | Belgium, Netherlands | 64 KB | £ keyboard |
| HX-10E, HX-10I, HX-10SF | Spain, Italy, Finland | 64 KB | Accent-key keyboard |
| HX-10F | France | 64 KB | RGB output |
| HX-10P | UK (also Germany, Italy) | 64 KB | £ keyboard, 240 V |
[1][2] The second-revision and European models use Toshiba's TCX-1007 gate array; the first Japanese models are built from separate chips.[1]
Hardware
[edit | edit source]The HX-10 has its mains transformer inside the case. On the British model it gives two unregulated AC outputs, 8.5 V and 16 V, which are rectified and regulated on the main board by discrete transistor and zener regulators: a B435 on an aluminium heat sink for +5 V, a D880 for +12 V and an A473 for −12 V.[4][5] The video RAM is eight 4116 chips, which also need a −5 V supply.[4][6]
The TMS9929A video chip has a heat sink glued on top. Its YPbPr video signals go over six wires to a separate PAL encoder board, an EMC PB3605E built round an LVA510 encoder, and the composite signal returns to the main board for the composite socket and the RF modulator.[4] The CPU is a Sharp Z80A in a socket, the 32 KB ROM an MB83256, and the main RAM eight HM4864AP chips.[4][5] A lever beside the cartridge slot opens the SW1/SW2 switch while a cartridge is going in.[4]
Owners report that the machine runs hot, mostly from the +5 V regulator transistor and its heat sink, and more so with power-hungry cartridges fitted.[5]
Connections
[edit | edit source]- Cartridge slot (top)
- Expansion bus (rear), for the HX-E600 slot expander and other Toshiba equipment
- Composite video, audio and RF outputs
- Cassette recorder socket
- Two joystick ports
- Centronics printer port (not on the HX-10S, HX-10D and HX-10SA)
- RGB output on the HX-10DPN and HX-10F instead of RF
Known faults
[edit | edit source]- Heat from the power supply, especially the +5 V regulator, which can push nearby capacitors past their temperature rating.[5]
- Black screen with the power LED on, often from the LVA510 PAL encoder.[8]
- A short on the +5 V rail after storage. Removing RAM chips raised the resistance, and forum members point to capacitors, RAMs, the video chips and the cartridge slot microswitch.[9]
- Wrong or missing supply voltages from a failed zener or regulator transistor in the supply section, including the −5 V feed to the video RAM.[6]
- A failing mains transformer with low AC outputs.[10]
Maintenance and repair
[edit | edit source]- Toshiba HX-10 General Maintenance
- Toshiba HX-10 Troubleshooting Guide
- Toshiba HX-10 Capacitor Replacement Guide
Documentation
[edit | edit source]- Toshiba HX-10 Owner's Manual, the English owner's manual for the British HX-10.
Related pages
[edit | edit source]References
[edit | edit source]- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 Toshiba HX-10, MSX Resource Center wiki—link(accessed 2026-10-21) Community page for the HX-10 series: Japanese HX-10S and HX-10SA (16 kB), HX-10D, HX-10DP and HX-10DPN (64 kB), sold as the Pasopia IQ; European HX-10AA, HX-10E, HX-10F, HX-10I, HX-10P and HX-10SF, all 64 kB; one cartridge slot and an expansion bus at the back for the HX-E600 slot expander; 1983 (HX-10S and HX-10D), 1984 for the others; UK price £279; RAM in slot 2 on 64 kB models; VDP TMS9918A, TMS9928A or TMS9929A depending on model; PSG AY-3-8910A; separate ICs on the HX-10S, HX-10D and HX-10SA, Toshiba TCX-1007 gate array on the others; Sharp LH0080A Z80A; RGB output (RP13A connector) only on the HX-10DPN and HX-10F; printer port except on the HX-10S, HX-10D and HX-10SA; data recorder connector on the right side on the HX-10S and HX-10D and on the back on the other models.
- ↑ 2.0 2.1 2.2 Toshiba HX-10P, MSX Resource Center wiki, 7 March 2026—link(accessed 2026-10-21) The HX-10P, usually labelled simply HX-10, is the British adaptation of the Japanese HX-10DP, with a 240 V power supply, also sold as a grey import in Germany and Italy; launch price £279 in late 1984, under £70 a year later; a starter kit from October 1985 at £139.99 with the HX-C810 data recorder, a book, software cassettes, a blank cassette, two plugs and a screwdriver.
- ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 Toshiba, Home Computer Owner's Manual, Model HX-10, 1984, chapter 6 "Specifications", printed page 44 (PDF page 46). See Toshiba HX-10 Owner's Manual. Z80A at 3.58 MHz; 64K RAM main memory; 32K ROM system memory; 16K RAM video memory; Microsoft Extended BASIC; RF and composite video outputs; VDP TMS 9929A; text 40 × 24 or 32 × 24, high resolution 256 × 192, multicolour 64 × 48; 32 sprites; 16 colours; 73 keys; audio output; PSG AY-3-8910; cassette FSK 1200/2400 baud; Centronics parallel printer interface; cartridge bus and expansion bus; two joystick ports; power consumption AC 240 V, 50 Hz, 17 W; 370 × 60 × 245 mm (W × H × D); 2.8 kg.
- ↑ 4.0 4.1 4.2 4.3 4.4 Toshiba MSX HX-10 64K: Electrónica– Alejandro Sánchez, 25 May 2021—link(accessed 2026-10-21) In Spanish. Teardown of an HX-10 64K (HX-10P): remove the screws under the case except those holding the transformer, and lift the top with the keyboard, which connects to the main board through a 9-pin and an 11-pin connector (three pins of the 11-pin one feed the two keyboard LEDs); the transformer (marked 240 V, works on 220 V) gives 8.5 V AC and 16 V AC, rectified and regulated on the main board by transistor and zener regulators: a B435 on a heat sink for +5 V, a D880 for +12 V and an A473 for −12 V; Sharp Z80A with a 3.579545 MHz resonator; eight HM4864AP-15 RAMs; TMS9929A under a glued heat sink; separate PAL encoder board EMC PB3605E with an LVA510 and a 4.433619 MHz crystal, fed from the VDP by six wires; RF modulator in a metal box with a channel adjustment screw; eight 4116 video RAMs; MB83256 32 KB ROM; cartridge slot with a lever switch joining SW1 and SW2; four HD74LS367AP buffers; TCX-1007 gate array; cassette motor relay. Author's replies of 8 and 14 January 2024: the two transformer outputs are unregulated AC.
- ↑ 5.0 5.1 5.2 5.3 My Toshiba HX-10 gets mighty hot!, December 2016 – March 2019—link(accessed 2026-10-21) Colemu: the heat comes from the regulator transistor TR8, a B435 on the aluminium heat sink next to the transformer (base 8.3 V, collector 5 V, emitter 9 V); the other two transistors, without heat sinks, are a D880 and an A473. gdx (whose HX-10 is the Japanese NTSC version): added small heat sinks to the two bare regulators; with a CF interface and a memory cartridge fitted the large heat sink reached 84.4 °C, the A473 about 72 °C and the D880 about 76 °C; the two capacitors nearest the hot regulator, 2200 µF 35 V and 4700 µF 16 V, were rated 85 °C, and he replaced the four largest capacitors with 105 °C parts; the CPU is socketed, and a CMOS Z80 lowered the temperature by a little over 3 °C; the transformer reached about 56 °C. sd_snatcher: Toshiba's MSX supplies run hot with heat sinks too small or missing; use Japanese models only on 100 V and European ones only at their rated voltage; avoid slot expanders without their own supply and very power-hungry cartridges; add heat sinks or a small fan; a CMOS Z80 of 10 MHz or less (not the Z84C0020) cuts the load; beware of fake Z80s. RetroTechie: TR8 works as a linear regulator from about 9 V down to 5 V, dissipating about 4 W at 1 A; a switching 78xx-type module rated 1.5 A or more in its place would cut the heat. A member, 14 April 2017: for power circuits near heat sources, choose 105 °C capacitors with a long rated life and bend their leads to keep them away from the heat. Kacper, 2019: a PAL HX-10 has a different main board; its large heat sink reached 77 °C after 20 minutes.
- ↑ 6.0 6.1 Toshiba HX-10 -- unusual black screen issue!, March 2025—link(accessed 2026-10-21) WxAxNxDxExRxExR: black screen with a faulty ROM replaced; the Z80, VDP, PAL board with its LVA510, PSG and ROM all tested good in a second HX-10. sdsnatcher73: check activity on the RAM and VRAM address and data lines with a scope or logic probe, the chip selects on the RAM and ROM, then the clock and reset on the VDP and CPU. Later: about 7 V on the chips, linked to the A473 PNP power transistor TR6; with TR6 replaced the chips still saw 6.5 to 7 V; no −5 V on the 4116 video RAMs, whose −5 V supply leads back to TR6 and smaller transistors and diodes; the zener ZD3 next to TR6 was found blown.
- ↑ Toshiba, Home Computer Owner's Manual, Model HX-10, 1984, "Safety precautions", "Controls and connections" and "Program loading from ROM cartridge" (PDF pages 4, 8, 9 and 16). See Toshiba HX-10 Owner's Manual. Mains supply 240 V 50 Hz; no plug supplied; fit a 13 A plug with a 3 A fuse (blue neutral, brown live); always switch off the computer before inserting or removing a ROM cartridge, as damage to the program on the cartridge may result. Front and right side: power indicator, cartridge slot. Rear and left side: expansion bus connector (only equipment specified by Toshiba should be connected to it), composite video output, audio output, RF output, cassette recorder socket, power switch, mains cord.
- ↑ My old MSX seems to be broken - any ideas?, November 2008—link(accessed 2026-10-21) An HX-10 64k after 12 years in storage: black screen, power LED on, Caps Lock not responding. Repair-Bas: if the power LED lights it is usually not the power supply; on a Toshiba it is mostly the LVA-510 PAL encoder. RetroTechie: check every supply voltage first; power LED on with a black screen and no Caps Lock usually means the Z80 is not running, from a clock, ROM or (more often) RAM fault; ageing brings bad sockets and connectors, broken tracks, and dried, leaking or shorted capacitors. PingPong: the VDP supplies the CPU clock.
- ↑ Toshiba HX-10 Repair, October 2021—link(accessed 2026-10-21) ArkadiuszMakarenko: after storage, a hard short from +5 V to ground; the large power transistors and zeners tested good. gdx and SkalTura: check the capacitors, look for bulges or leaks, lift the ones on the 5 V circuit one at a time. Wierzbowsky: check the cartridge slot, the rear expansion connector and the joystick ports for shorts, then the transistors and regulators, then the capacitors; even a ceramic capacitor can short the rails. ArkadiuszMakarenko: removing 4164 RAMs raised the resistance from about 3 ohms towards 300 ohms. gdx, 6 October 2021: the usual causes are capacitors, RAMs and VRAMs, the video circuit chips and the microswitch in the cartridge slot, or bad contacts of socketed chips; check each electrolytic for a short with an ohmmeter.
- ↑ HX-10 Faulty transformer, December 2021—link(accessed 2026-10-21) jonwarby: a European HX-10 measured at the transformer connector with the main board unplugged gave about 20 V AC on the blue lead but only 2 to 3 V AC on the grey and brown leads, where about 9 V was expected; the supply is AC only, with the DC conversion on the main board. Manuel: also check for +5 V, +12 V and −12 V DC.