Commodore PET 2001
The Commodore PET 2001 (Personal Electronic Transactor) was Commodore’s first all-in-one personal computer, introduced in 1977. It featured an integrated keyboard, monitor, and cassette tape drive in a compact metal case. Originally released with either 4 KB or 8 KB of RAM, the PET 2001 was designed as a turnkey educational and business machine and helped establish Commodore as a major force in early personal computing.
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| Commodore PET 2001 with built-in cassette drive | |
| Specifications | |
|---|---|
| Manufacturer | Commodore International |
| Type | Personal Computer |
| Released | 1977 |
| Discontinued | 1982 |
| Intro price | US$795 (2001-4), US$995 (2001-8) |
| CPU | MOS Technology 6502 @ 1 MHz |
| Memory | 4 KB – 8 KB (expandable to 32 KB) |
| Storage | Integrated cassette deck, external IEEE-488 floppy drive (optional) |
| Display | 9" monochrome built-in CRT (40x25 text) |
| Sound | None (no built-in audio hardware) |
| Dimensions | 19" H × 17" W × 19" D (approx.) |
| Weight | ~20 kg |
| OS / Firmware | Commodore BASIC 1.0 / 2.0 |
| Predecessor | None |
| Successor | Commodore PET 2001-N |
| Codename | PET |
| Model no. | 2001-4, 2001-8 |
The machine shipped with Commodore BASIC stored in ROM and was one of the first computers available as a fully assembled unit — an innovation that made it accessible to a broader audience than kit-based computers of the era.
🧰 General Maintenance
Over decades of operation, PET 2001 systems are prone to failures caused by aging electrolytic capacitors, worn-out ROM sockets, and stuck cassette mechanisms. Routine cleaning, contact reseating, and power supply testing are essential.
For detailed cleaning, CRT safety, keyboard servicing, and PRAM battery handling (where present), see the Commodore PET 2001 Maintenance Guide.
🧾 PCB Schematics & Service Guide
The PET 2001 logic board layout is relatively simple, with discrete TTL logic, a MOS 6502 CPU, and rows of DRAM chips depending on the model.
📷 Logic Board Images
| Logic Board | Schematic Diagrams |
|---|---|
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📚 Resources
The following pages contain the complete internal schematics and service manuals:
🔌 Common Issues & Troubleshooting
- Blank screen on power-up: Check the 6502, RAM, and character ROMs.
- "garbage characters" on boot: Often caused by faulty RAM or ROM chips.
- Cassette load errors: Clean or replace the drive belt; inspect the tape head for alignment.
- Keyboard not responding: PETs used a capacitive keyboard matrix prone to oxidation; see the Commodore PET 2001 Keyboard Repair Guide.
For a full list of common faults and fixes, visit the Commodore PET 2001 Troubleshooting Guide.
🔄 Capacitor Replacement
While the PET series lacks the surface-mount capacitor plague seen in later machines, their power supplies and logic boards still suffer from degraded electrolytics.
Refer to the Commodore PET 2001 Capacitor Replacement Guide for a complete bill of materials and safe removal/replacement procedures.