Commodore PET 2001 Service Documentation
Commodore's own service documentation for the Commodore PET 2001 survives in reasonable completeness. Four documents are hosted here, and together they cover both assemblies inside the machine at component level.
They are the source for every figure on Commodore PET 2001 Capacitor Replacement Guide.
Parts lists
- 8K Main Logic Assembly Parts Cross Reference — every component on the system board by reference designator, description and Commodore part number. Carries a text layer.
- Display Assembly Component Cross Reference — the same for the 9-inch monitor and power board, which is also where the machine's mains transformer and reservoir capacitor live.
Schematics
- Main logic schematic, assembly 320008 — three sheets. Sheet 1 is drawing 320130, circuitry common to all PET computers; sheets 2 and 3 are drawing 320026 and are specific to assembly 320008.
- Schematic, Service, Display Circuit — the monitor and supply board, with the oscilloscope settings for the waveform photographs printed on the drawing.
The four original board assemblies
Commodore's note on sheet 3 of the main logic schematic records that all component locations are the same on all four boards; only the fitted components differ, and the identifying board number is silkscreened in the upper left corner.[1]
| Assembly | ROMs | RAM | Schematic |
|---|---|---|---|
| 320008 | 6540 | 6550 | 320026 |
| 320081 | 2316B | 6550 | 320082 |
| 320132 | 6540 | 2114 | 320130 |
| 320137 | 2316B | 2114 | 320135 |
All four are variants of the original static board. The later 2001-N / 3000 / 4000 dynamic system board is a different design and is not covered by these documents; for those machines see Commodore PET 4000 Series.[2]
What these documents establish
- The only aluminium electrolytics on the main logic board are C7–C10, 47 µF 16 V. C5, C11, C12 and C13 are 1 µF 25 V tantalums; C15–C49 are 0.1 µF ceramics.[3]
- The 4700 µF 25 V reservoir is C1 on the display assembly, not on the system board.[4]
- The main logic board carries no voltage regulator. It receives +5 V and a +9 V unregulated rail from elsewhere in the machine.[3]
- The display assembly generates +12 V, a +85 V boost rail, −30 V and roughly +10 kV for the CRT anode.[5]
- The master crystal Y1 is 8 MHz.[1]
Related pages
References
- ↑ 1.0 1.1 Commodore Business Machines, PET Computer Main Logic schematic, drawings 320130 (sheet 1) and 320026 (sheets 2–3), for board assembly 320008. Hosted here as File:Commodore PET 2001 Main Logic Schematic (320008).pdf. Sheet 3 carries Commodore's note that component locations are common to assemblies 320008, 320081, 320132 and 320137.
- ↑ zimmers.net Commodore PET schematics index. Directory listing distinguishing the original 2001 static board from the 2001N/3000/4000 dynamic system board, and naming the four static-board variants and their schematic numbers. A secondary source for the directory structure; the assembly numbers themselves are confirmed by Commodore's own note on the schematic.
- ↑ 3.0 3.1 Commodore Business Machines, 8K Main Logic Assembly Parts Cross Reference for the PET 2001. Hosted here as File:Commodore PET 2001 Main Logic Assembly Parts List.pdf. Gives every component on the system board by reference designator, description and Commodore part number.
- ↑ Commodore Business Machines, Display Assembly Component Cross Reference for the PET 2001. Hosted here as File:Commodore PET 2001 Display Assembly Parts List.pdf. Numbered list of every component on the monitor and supply board.
- ↑ Commodore Business Machines, Schematic, Service, Display Circuit for the PET 2001, with the supplementary sheet of oscilloscope settings. Hosted here as File:Commodore PET 2001 Display Circuit Schematic.pdf. Shows CR19–CR22, C1, VR1, the +85 V boost and −30 V rails, the flyback T2 and the +10 kV anode supply, and the deflection yoke figures.