VIC-20
The friendly computer.
Open the VIC-20 in Retro Bench- Also
- VC-20 / VIC-1001
- Year
- 1981
- CPU
- 6502 @ 1 MHz
- RAM
- 5 KB (3583 bytes free)
- ROM
- BASIC 2.0 (8K) + KERNAL (8K) + char (4K)
- Video
- VIC 6560/6561
- Sound
- VIC 6560/6561 (3 tones + noise)
- OS
- Commodore BASIC 2.0
Chips
| Chip | Where | Role |
|---|---|---|
| 6560 / 6561 VIC-I | UB7 | Video, sound, paddles, light pen, CPU clock |
| 6502 / 65C02 CPU | UE10 | CPU |
| 6522 VIA | UAB1, UAB3 | Two 8-bit ports, timers, serial and user port |
| 2114 SRAM 1K x 4 | UD2, UE1, UE2, UD3-UE6 | Static RAM (ZX80 and ZX81 1K) |
| 2364 Mask ROM 8K×8 | UE11 (BASIC 901486-01), UE12 (KERNAL 901486-06/-07) | BASIC and KERNAL ROMs (C64); BASIC and KERNAL (VIC-20, PET); character ROM (C128) |
| 2332 Mask ROM 4K×8 | UD7 (character 901460-03) | Character ROM (C64, VIC-20, PET) |
Ports and connectors
- Power in (9 V AC), 2-pin power jack (J1)
- Serial (IEC) disk / printer, DIN-6
- Video and audio, DIN-5 (180°)
- User port, 24-contact card edge (2 × 12)
- Memory expansion / cartridge port, 44-contact card edge (2 × 22)
- Control port, DE-9 male
- Cassette port (Datasette), 12-contact card edge (2 × 6)
Power rails
| Rail | Expect | Measure at |
|---|---|---|
| +5 V | +5 V | 6502 pin 8; LM323 VR1 output |
| 9 V AC in | About 9 V AC between the two 9 V AC pins | Power jack J1; vic20-user pins 10, 11 (user port) |
Symptoms
- Black or blank screen: check 6502, 2364
- Garbage screen: check 2114, VIC
- No picture or sound: check VIC
- Dead keyboard or joystick: check VIA
- No serial or cassette: check VIA
- Garbled characters: check 2332
- Dead machine, no boot: check VIC, 6502, 2114