C:\>ConventionalMemory.io

Recap guide

Recap the Commodore PET 2001

Mostly a RAM and ROM machine, but one repair report found rectifier-circuit caps failing together with bad RAM chips.

Open the interactive checklist Tick off each capacitor as you replace it. It saves in your browser.

Check first. A recap is not always the answer here, so look at the guides before you order parts.

Which board do I have?

Boards changed during production. These notes come from the linked sources, and many are only partly documented, so check the board in front of you.

  • PET 2001 static RAM boards (320008, 320081, 320132, 320137) (Medium confidence). How to tell: Four variants of the original board differ by ROM and RAM type (6540 or 2316B ROMs, 6550 or 2114 RAMs) per the schematic index. Capacitors: A 2001-8 repair report mentions failed caps serving the rectifier diodes but no list. Capacitor list differs from other revisions: not known. Source
  • 2001N, 3000 and 4000 dynamic board (Low confidence). How to tell: Dynamic RAM board without CRTC used with 9 inch screens. Capacitors: No capacitor lists found. Capacitor list differs from other revisions: not known. Source

Where to start

Clues from write-ups and forum threads, not a diagnosis. Low confidence means one thread or one repair; high means several write-ups agree.

  • Rectifier caps (Low confidence). In one PET 2001-8 mainboard repair, the caps on the rectifier diodes failed along with RAM chips. Source

Tips, tales and maybes

Found in write-ups and forum threads. These are other people's reports, not tested by us. Check part references and values against your own board.

  • Story: Garbage screen was ROM and video RAM (Low confidence). A blog repair of a PET (model unspecified) with a garbage screen and dead keys found no ripple on the supply, a stuck 2114 video RAM and two bad ROMs. The author says RAM, video RAM and ROM failures came next after supply faults and dry joints. Source
  • Tip: Tape load pulls the 5V down; check the Molex (mirror of cctalk) (Low confidence). In a mirrored cctalk thread on a PET 2001-16N, a reply says the tape motor load was dragging the unregulated supply down so the 5V line sagged. It points to the white 0.156 inch Molex power connector overheating (brown plastic means replace) and to drying smoothing caps, especially the big ones off the main board. Source
  • Tip: Loud hiss with no smoke (Low confidence). A PET thread says a loudly hissing monitor with no smoke may only be the picture tube suction cup connector having come loose, and one user confirmed reseating it with the power off stopped the hiss. Garbled cassette loads can be tested with an external tape drive. Source

Before you start

  • Boards changed during production. Check your board number against the guides before you order parts.

Guides we used

This page and the interactive bench are built from these. They have the photos and the full detail, so please read them and support their authors.

The capacitor list

We have not checked a capacitor list for this machine yet, so none is shown. Follow the guide above for your board, then add the capacitors in the interactive checklist and it builds a shopping list for you.

Skip the sourcing

While you are in there

Affiliate links. As an Amazon Associate I earn from qualifying purchases. These links only search by name. Disclosure

Steps, tools and safety

The steps, the tools in top, middle and budget picks, and the safety list are the same for every machine, so they live on one page: How to recap, step by step.

Values are shown as published in the guides above, and boards changed during production. Check the board in front of you. A recap involves hot tools and, on some machines, dangerous voltages. You do it at your own risk.

More