JVC HC-7
.png) | |
| The HC-7GB, the UK version, as drawn on the cover of JVC's instructions | |
| Specifications | |
|---|---|
| Manufacturer | Victor Company of Japan (JVC) |
| Type | MSX home computer |
| Released | 1985[1] |
| Intro price | ¥84,800 (Japan); £279 (United Kingdom)[1][2] |
| CPU | Sharp LH0080A (Z80A), 3.58 MHz |
| Memory | 64 KB RAM, 16 KB video RAM, 32 KB ROM |
| Storage | Cassette, cartridges |
| Display | Texas Instruments TMS9928A (Japan), TMS9929A (Europe) |
| Sound | General Instrument AY-3-8910A |
| Power | 240 V AC ±10%, 50 Hz, 12 W (HC-7GB); 220 V (HC-7E) |
| Dimensions | 382 × 86 × 286 mm (HC-7GB) |
| Weight | 2.7 kg (HC-7GB) |
| OS / Firmware | — |
| Model no. | HC-7 (Japan), HC-7GB (UK), HC-7E (Europe) |
The JVC HC-7 is an MSX home computer made by the Victor Company of Japan. It was sold in Japan in 1985 as the Victor HC-7, JVC's first computer of its own design, and in Europe as the JVC HC-7GB and HC-7E.[1][2] Its two cartridge slots are on the right-hand side and at the back of the case.[3]
Versions
[edit | edit source]| Model | Market | Differences |
|---|---|---|
| Victor HC-7 | Japan | Superimposer (HC-A602S module built in), firmware menu and extra BASIC commands, audio balance slider, TMS9928A video chip |
| JVC HC-7GB | United Kingdom | No superimposing or firmware; monitor connector in place of the monitor/VTR connector; no balance slider; TMS9929A; 240 V supply |
| JVC HC-7E | Europe | As the HC-7GB, with a 220 V supply |
[1][2][4] The HC-A602S module was removed from most export machines, but the RGB output it fed was kept.[2] The BASIC ROM of an HC-7E has been found identical to the HC-7GB's.[5]
Specifications
[edit | edit source]| Item | Figure |
|---|---|
| CPU | Z80A compatible, 3.58 MHz |
| Memory | 64 KB RAM, 32 KB ROM (MSX-BASIC) |
| Text | 32 or 40 characters × 24 lines |
| Graphics | 256 × 192 dots, 16 colours, 32 sprites |
| Sound | 8 octaves, 3 voices and noise |
| Power | 240 V AC ±10%, 50 Hz, 12 W |
| Operating conditions | 0 to 35 °C, 80% relative humidity or less |
| Size | 382 (W) × 86 (H) × 286 (D) mm |
| Weight | 2.7 kg |
Hardware
[edit | edit source]The main board of an HC-7E, marked EA-1202A MAIN CK-10249-B02, carries a Sharp LH0080A processor, a Hitachi HD27L019 gate array, a Mitsubishi M5L8255AP-5 peripheral interface, an AY-3-8910A sound chip, eight TMM4164AP-15 chips as the 64 KB of RAM and eight MB8118-12 chips as the 16 KB of video RAM.[4][7] The video chip sits under a small heat sink.[8] There is no MSX-Engine chip.[1]
The BIOS ROM is in slot 0 and the RAM in slot 2. The side cartridge slot is primary slot 1 and the rear slot is primary slot 3, although JVC's manual labels them "slot 1" and "slot 2".[1][3]
The power supply is a separate board inside the case. It feeds the main board through connector CN001 with four supply wires and a fifth, yellow, inhibit wire.[9] Switches at the cartridge slot covers pull that wire up and turn the supply off.[4][8] The keyboard uses microswitches.[4]
Connections
[edit | edit source]The rear panel has the RF output, the reset button, the printer connector, the data recorder socket, the monitor socket, the RGB (SCART) socket, the power switch and the mains lead; the joystick ports are on the left side.[3] The monitor socket is a 5-pin DIN carrying composite video and sound, and the RF output is on UHF channel 36.[10]
Known faults
[edit | edit source]- Blue flash then a black screen at switch-on: one HC-7E with this fault ran from a RAM cartridge but not from its own RAM, and replacing the RAM chips did not cure it.[8]
- Intermittent power-on that responds to tapping near the power supply.[5]
- The machine switching off when a slot cover switch is pressed is normal: it is the supply's interlock.[8]
The JVC HC-7 Troubleshooting Guide covers these.
Documentation
[edit | edit source]No service manual for the HC-7 is among the MSX service manuals held by the MSX Archive, and the owner of the faulty HC-7E above could not find one.[11][8] JVC's owner's manual for the HC-7GB is hosted here as File:JVC HC-7GB Instructions.pdf. JVC's MSX BASIC Guide for the HC-7GB is on the Internet Archive.[2]
Repair guides
[edit | edit source]Related pages
[edit | edit source]References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Victor HC-7, MSX Resource Center wiki, 30 May 2026—link(accessed 2026-10-21) Community page: JVC's first own computer; Japan, 1985, ¥84,800; 64 KB RAM in slot 2, 16 KB VRAM; TMS9928A; AY-3-8910A; no MSX-Engine, separate ICs including a Hitachi HD27L019 gate array; reset button, superimposer (HC-A602S module built in), audio balance slider, Victor BASIC and a firmware menu (Tiny Joygraph, printer select, monitor); Sharp LH0080A Z80A at 3.58 MHz; slot map slot 0 main ROM, slot 1 cartridge slot 1, slot 2 RAM, slot 3 cartridge slot 2; connections RF, DIN monitor output with composite video and stereo audio, RGB21 input/output, data recorder, Centronics printer, two general ports, two cartridge slots. Exported without the superimposing features and firmware as the HC-7E and HC-7GB.
- ↑ 2.0 2.1 2.2 2.3 2.4 JVC HC-7GB, MSX Resource Center wiki, 8 May 2026—link(accessed 2026-10-21) Community page: the HC-7 localised for Great Britain with a £ key; superimposing and firmware ROM removed; the Monitor/VTR record connector replaced by a monitor connector and the balance slider removed; the HC-A602S module removed in most examples while the RGB output it fed was kept; dark silver; apparently the same as the HC-7E apart from the power supply (240 V instead of 220 V); £279; 64 KB RAM in slot 2; TMS9929A; AY-3-8910A; HD27L019 gate array; Sharp LH0080A; connections RF, RGB (SCART), monitor, data recorder, printer, two general ports, two cartridge slots.
- ↑ 3.0 3.1 3.2 Victor Company of Japan, Instructions, Personal Computer HC-7GB. Hosted here as File:JVC HC-7GB Instructions.pdf. Printed page 6 (PDF page 8), "Names of parts": power indicator, CAPS mode indicator, keyboard; rear panel with RF output connector, reset switch, printer connector, data recorder connector, monitor connector, RGB connector, power switch, power cable and the rear slot (slot 2); side slot (slot 1) on the right side; joystick 1 and 2 connectors on the left side.
- ↑ 4.0 4.1 4.2 4.3 JVC HC-7E, MSX Resource Center wiki, 8 May 2026—link(accessed 2026-10-21) Community page: the HC-7 localised for Europe, the same as the HC-7GB except for the power supply (220 V instead of 240 V); hardware details Sharp LH0080A Z80A-CPU-D, eight TMM4164AP-15 DRAMs as RAM, TMS9929A, eight MB8118-12 DRAMs as VRAM, AY-3-8910A; the internal power supply joins the main board through a 6-pin female Molex connector with black ground, red +5 V, orange +12 V and blue −12 V, and a yellow wire that switches the supply off when the cartridge lid is open, at about 0.14 V with the lid closed and 0.93 V with it open; keyboard on microswitches.
- ↑ 5.0 5.1 For sale: JVC HC-7E MSX, January 2017—link(accessed 2026-10-21) The seller dumped the BASIC ROM of an HC-7E and found it identical to the HC-7GB's; the bottom plate gives 220 V; the seller later reported that the machine did not always power on, but tapping around the power supply made it work. A reply noted that the HC-7GB main board in the MSX Resource Center's photograph carries added resistors beside the large blue capacitor to the left of the Z80, which the HC-7E board has built in.
- ↑ JVC, Instructions, Personal Computer HC-7GB, page 34 (PDF page 34), "Hardware specifications". See File:JVC HC-7GB Instructions.pdf.
- ↑ File:JVC HC-7E main board.jpg, photograph of the inside of an HC-7E uploaded to the MSX Resource Center wiki by Gdx on 1 April 2016. Read from it: main board marked "EA-1202A MAIN CK-10249-B02"; Sharp LH0080A, Hitachi HD27L019, Mitsubishi M5L8255AP-5, GI AY-3-8910A, eight TMM4164AP-15 and eight MB8118-12; a daughterboard at the top left; the power supply board and RF modulator at the top right, joined to the main board by a coloured harness; electrolytic capacitors including C273, C274 and C275 along the lower edge beside the RAM.
- ↑ 8.0 8.1 8.2 8.3 8.4 Got a JVC hc-7e worked at first but now refueso to power on, March to November 2016—link(accessed 2026-10-21) Four-page repair thread on an HC-7E that showed a blue screen for under a second and then black, with Caps Lock dead. Readings at the supply connector with the machine on: blue −11.77 V, yellow 0 V, orange +11.60 V, red +5.0 V. The owner found that pressing the microswitches at the cartridge slots raised the yellow wire to about 1 V and switched the machine off; a reply called it the supply's inhibit line, normally at 0 V. Replies identified the LH0080 as the Z80, the M5L8255AP as an 8255, the chip under the heat sink as the VDP and the HD27L019 as a custom chip; gave the 4164 supply pins as +5 V on pin 8 and ground on pin 16; asked for the 3.58 MHz clock to be checked on pin 6 of the Z80 and for the reset inputs to be watched on Z80 pin 26, VDP pin 34 and 8255 pin 35 while pressing reset. The machine started with a flash cartridge carrying its own RAM (the owner's MegaFlashROM SD and RAM cartridge) in a slot; RAM tests passed; replacing all the RAM chips did not cure it, and the last advice was to check the cartridge slots for bent or shorted pins and the board for short circuits.
- ↑ File:JVC HC-7E power supply connector.jpg, photograph uploaded to the MSX Resource Center wiki by Mcolom on 26 November 2022: main board connector CN001, a six-way Molex housing carrying blue, yellow, orange, black and red wires from left to right, with one position empty.
- ↑ JVC, Instructions, Personal Computer HC-7GB, pages 35 to 38 (PDF pages 35 to 38), "Interfaces": cassette, FSK at 1200 baud (default) or 2400 baud, 8-pin DIN (1, 2, 3 and 8 ground, 4 CMTOUT, 5 CMTIN, 6 REM+, 7 REM−); A/V, PAL, 5-pin DIN (2 ground, 3 sound, 4 video); general-purpose I/O on 9-pin D connectors; printer, 8-bit parallel Centronics, 14-pin; cartridge bus, 50-pin, with +5 V on pins 45 and 47, +12 V on 48, −12 V on 50 and ground on 41 and 43; RGB connector (SCART): audio out on pins 1 and 3 (500 mV rms, 1 kΩ), blue, green and red out on 7, 11 and 15 (0.7 V p-p, 75 Ω), status CVBS on 8 and status RGB on 16 ("H", pull-up), sync out on 19 (0.5 V p-p, 75 Ω, negative); RF out, PAL CCIR I channel 36, RCA. See File:JVC HC-7GB Instructions.pdf.
- ↑ Index of /pub/msx/docs/service_manuals, MSX Archive—link(accessed 2026-10-21) Directory of MSX service manuals; it lists none for JVC or Victor machines.
