250425-01 (B)
- 8-pin board (reduced oscillator circuit).
- PCB Assembly Number 250425-01.
- Schematic Number 251469.
- CIAs, ROMs, CPU, SID, PLA, and VIC may be all socketed.
Integrated Circuits
| PCB Identifier | Chip Number | Remarks | Memory Location/bit |
|---|---|---|---|
| U1 | 6526 | CIA 1 | $DC00-$DCFF |
| U2 | 6526 | CIA 2 | $DD00-$DDFF |
| U3 | 2364 | Basic ROM | $A000-$BFFF |
| U4 | 2364 | Kernal ROM | $E000-$FFFF |
| U5 | 2332 | Character ROM | $D000-$DFFF |
| U6 | 2114L-30 | SRAM 1Kx4 | $D800-$DBFF |
| U7 | 6510 | CPU | |
| U8 | 7406/7416 | Logic NOT (Hex Inverter) | |
| U9 | 4164 | DRAM 64Kx1 | D1 |
| U10 | 4164 | DRAM 64Kx1 | D3 |
| U11 | 4164 | DRAM 64Kx1 | D5 |
| U12 | 4164 | DRAM 64Kx1 | D7 |
| U13 | 74LS257 | Multiplexor | |
| U14 | 74LS258 | Multiplexor | |
| U15 | 74LS139 | Demultiplexor | |
| U16 | 4066 | Quad Bilateral Switch | |
| U17 | 82S100 / 906114-01 | PLA | |
| U18 | 6581 | SID | $D400-$D7FF |
| U19 | 6567 (NTSC)/6569 (PAL) | VIC-II | $D000-$D3FF |
| U20 | LM556 | Dual Timer | |
| U21 | 4164 | DRAM 64Kx1 | D0 |
| U22 | 4164 | DRAM 64Kx1 | D2 |
| U23 | 4164 | DRAM 64Kx1 | D4 |
| U24 | 4164 | DRAM 64Kx1 | D6 |
| U25 | 74LS257 | Multiplexor | |
| U26 | 74LS373 | 8 bit 3-state Latch | |
| U27 | 74LS08 | Logic AND | |
| U28 | 4066 | Quad Bilateral Switch | |
| U31 | 7701/8701 | Oscillator |
Schematics
Board Image
