System Board Parts List (2 of 3)
Sheet 2 of Commodore's Main Logic Assembly Parts Cross Reference for the Commodore PET 2001 lists the integrated circuits on the main logic board, from UA2 to UH3, by reference designator, description and Commodore part number. Sheet 1 covers the passive parts, transistors, connectors and the first ICs; sheet 3 has the remaining ROMs and the sockets. The sheets carry the Commodore Business Machines, Palo Alto letterhead. The zimmers.net Commodore archive, the source of the scans, describes them as very early lists that do not include any upgrade ROMs.[1]
Contents
[edit | edit source]| Ref. des. | Description | Part no. |
|---|---|---|
| UA2 | 2316B-08 character generator | 901447-08 |
| UA5 | 6522 VIA | 901437-01 |
| UA7, UA8, UA9 | MC3446 interface bus | 901524-01 |
| UB1, UE8, UE9 | 74LS20 NAND gate | 901521-04 |
| UB2 | 74LS165 shift register | 901521-12 |
| UB3, UB4, UG5, UG6, UH8, UH9 | 74LS244 buffer | 901521-13 |
| UB6, UC5, UC7, UC8, UD5 | 74LS107 flip-flop | 901521-08 |
| UB8, UG8 | 6520 PIA | 901436-01 |
| UC1 | 74LS74 flip-flop | 901521-06 |
| UC2, UD8, UG3 | 74LS00 NAND gate | 901521-01 |
| UC3, UC4, UI1-UI8, UJ1-UJ8 | 6550 RAM | 901438-01 |
| UC3, UC4, UI1-UI8, UJ1-UJ8 | 2114 RAM | 901453-01 |
| UC6, UE2 | 74LS08 | 901521-03 |
| UD2, UD3, UD4 | 74LS157 data selector | 901521-11 |
| UD6, UD7 | 74177 counter | 901522-03 |
| UD9, UE5 | 74LS04 hex inverter | 901521-02 |
| UDE9 | LM555 timer | 901523-01 |
| UE3, UE4 | 7417 hex buffer | 901522-01 |
| UE6 | 74100 latch | 901522-02 |
| UF3 | 6502 MPU | 901435-01 |
| UG2 | 74LS154 decoder | 901521-10 |
| UG4 | 74LS21 AND gate | 901521-05 |
| UG9 | 74LS145 | 901521-09 |
| UH1 | 6540-011 ROM | 901439-01 |
| UH1 | 2316B-01 ROM | 901447-01 |
| UH2 | 6540-013 ROM | 901439-02 |
| UH2 | 2316B-03 ROM | 901447-03 |
| UH3 | 6540-015 ROM | 901439-03 |
| UH3 | 2316B-05 ROM | 901447-05 |
Reading the sheet
[edit | edit source]The RAM line appears twice against the same eighteen positions, once for the 6550 and once for the 2114, and each ROM position has a 6540 line and a 2316B line. One list covers all four versions of the static board. Commodore's schematic note says component locations are the same on assemblies 320008, 320081, 320132 and 320137 and only the fitted parts differ.[2] The zimmers.net archive lists 320008 with 6540 ROMs and 6550 RAM, 320081 with 2316B ROMs and 6550 RAM, 320132 with 6540 ROMs and 2114 RAM, and 320137 with 2316B ROMs and 2114 RAM.[1]
Sheet 1 gives the character generator at UA2 as a 6540-010 (901439-08); this sheet gives it as a 2316B-08 (901447-08).
The LM555 is listed at "UDE9". Schematic 320130 sheet 1 uses the same label for the timer.[2]
What the parts list does not contain
[edit | edit source]None of the three sheets lists the four +5 V regulators VR3-VR6 on the logic board, although sheet 1 lists their rectifiers CR1-CR3 (1N5402) and the 47 µF 16 V capacitors C7-C10 on their outputs. Schematic 320026 sheet 2 shows the regulators beside power connector J8.[2] The mains transformer, fuse and main reservoir capacitor are in the case, not on the board.[3] The display assembly has its own list, beginning at Video Board Parts List (1 of 3).
Related pages
[edit | edit source]- System Board Parts List (1 of 3) and System Board Parts List (3 of 3)
- 2001 Main Logic Assembly, the same three sheets as one PDF
- Schematic 320026 (Complete, Board 320008) and Schematic 320130 (Sheet 1 of 3, Static PET)
- Commodore PET 2001 Service Documentation
- Commodore PET 2001 Troubleshooting
Download: parts-2.gif
References
[edit | edit source]- ↑ 1.0 1.1 zimmers.net Commodore archive, /pub/cbm/schematics/computers/pet/2001/ directory listing (retrieved 2026-10-01). Source of parts-1.gif to parts-6.gif, video-1.gif to video-3.gif and video-layout.gif, with the archive's description of each file and of the four static-board assemblies.
- ↑ 2.0 2.1 2.2 Commodore Business Machines, PET Computer Main Logic schematic, drawings 320130 (sheet 1, common to all PET computers) and 320026 (sheets 2-3, assembly 320008), hosted as File:Commodore PET 2001 Main Logic Schematic (320008).pdf. Sheet 1 shows the LM555 timer labelled UDE9; sheet 2 shows power connector J8, rectifiers CR1 and CR2 (1N5402) and regulators VR3-VR6, and carries the note that all locations are the same on boards 320132, 320081, 320137 and 320008.
- ↑ PET-Shack (P.S. Software House), PET 2001 schematic and data-sheet bundle, c. 1978, hosted at File:PET-Shack PET 2001 Bundle.pdf. Third-party, not a Commodore document. Its "PET console wiring" drawing shows the power switch and a 1.8 A fuse on the transformer primary, a 16.2 V AC winding to the video monitor, and a 15.7 V AC centre-tapped winding to the logic board's 5-pin connector with a 23,000 µF 15 V capacitor.