Amstrad CPC 464
Keyboard, tape deck and a monitor that is also the power supply.
Open the Amstrad CPC 464 in Retro Bench- Also
- CPC464 (Schneider CPC 464), built-in cassette
- Year
- 1984
- CPU
- Z80A @ 4 MHz
- RAM
- 64 KB (eight 4164 DRAM)
- ROM
- 32 KB (OS firmware + Locomotive BASIC 1.0)
- Video
- Gate Array + 6845: 160 x 200 x 16, 320 x 200 x 4, 640 x 200 x 2 colors from 27
- Sound
- AY-3-8912, 3 voices, stereo jack
- OS
- Locomotive BASIC 1.0
Chips
| Chip | Where | Role |
|---|---|---|
| Amstrad 40007 / 40008 Gate Array (20RA043) | IC116 (20RA043 = Amstrad 40007; 40008 is pin compatible) | Video (pixels, palette, RGB, sync), DRAM timing, ROM/RAM selection, CPU clock and wait states, interrupts |
| Amstrad 40010 Gate Array (HSG3130 / HSG3170) | IC116 on later boards (AMS40010, per the amendment) | Video (pixels, palette, RGB, sync), DRAM timing, ROM/RAM selection, CPU clock and wait states, interrupts |
| Z80A CPU | IC111 (Z8400APS) | Main CPU (8-bit, 40-DIP) |
| MC6845 CRT controller | IC108 (HD6845SP) | Makes sync, display enable, cursor and the video RAM refresh addresses. |
| 23256 mask ROM 32K x 8 | IC103 (TMM23256P-1950; Amstrad 40009 on later boards), BASIC 1.0 | 32K x 8 mask ROM in the 27256 pinout. |
| 4164 DRAM 64K×1 | IC117-IC124 (HM4864U-2; KM4164B-15 on later boards) | Main RAM (8 chips = 64 KB) |
| 8255A-5 programmable peripheral interface | IC107 (M5L8255AP-5; TMP8255AP later) | Three 8-bit programmable I/O ports (A, B, C). |
| AY-3-8912 sound chip | IC102 | Three-voice programmable sound generator with one 8-bit I/O port |
Ports and connectors
- 5V DC socket (from the monitor), DC jack (Hosiden HEC0470-01-630, Amstrad part 170024; spec sheet calls it a 5 mm socket) UNVERIFIED
- Monitor socket (RGB), 6-pin DIN 240 degrees
- Joystick port, DE-9 male on the computer (9 pin D)
- Expansion port (rear), 50-way 0.1 in PCB edge (25 + 25), slot between 21/23 and 22/24
- Printer port (rear), 34-way 0.1 in PCB edge (17 + 17), Centronics numbering 1-17 / 19-35
- Stereo socket (headphones / amplifier), 3.5 mm stereo jack
Power rails
| Rail | Expect | Measure at |
|---|---|---|
| +5 V | +5 V | Z80A pin 11; 40007 pin 22; 40007 pin 38; 6845 pin 20; 8255A pin 26 |
| +5 V via R138 | Just under the +5 V rail | 40007 pin 9; 40007 pin 33 |
| GND | 0 V | Z80A pin 29; 40007 pin 35; 6845 pin 1 |
Symptoms
- Red power LED on, black screen: check 40007, 40010, Z80A, 23256, 6845, 4164
- Screen of garbage or a fixed pattern, no sign-on: check 4164, 40007, 23256
- Faults that start after a few minutes: check 40007
- Sign-on, then no color or wrong colors: check 40007, 40010
- No sound from speaker or stereo jack: check AY-3-8912, 8255A
- Rows of keys or the joystick dead: check AY-3-8912, 8255A
- Tape will not load: check 8255A