Commodore PET 4000 Series Maintenance Guide: Revision history

23 September 2026

• curprev 20:0520:05, 23 September 2026 Josh talk contribs 10,552 bytes +5,799 Replace the generic copied PSU/CRT text with Commodore's own drawing data: the +5 V regulator is an LM323 not a 7805, there are three regulators on the logic board and none in the supply chassis, the -5 V rail is real on this machine (unlike the PET 2001), C1 is 23,000 uF, F1 is 1.6 A slow-blow; remove the unsupported RIFA X2 instruction and the unsourced 6.3 VAC filament figure; add Commodore's electrolytic list undo

12 May 2025

• curprev 08:2508:25, 12 May 2025 Josh talk contribs 4,753 bytes −36 No edit summary undo

17 April 2025

• curprev 19:5819:58, 17 April 2025 Josh talk contribs 4,789 bytes −6 No edit summary undo Tag: Visual edit
• curprev 19:5619:56, 17 April 2025 Josh talk contribs 4,795 bytes +4,795 Created page with "thumb|376x376px|Commodore PET 4032 with top panel lifted. Proper maintenance of the '''Commodore PET 4000 Series''' is essential to preserve functionality and prevent age-related failures. This guide covers cleaning, keyboard servicing, capacitor replacement, power supply care, and CRT-specific issues unique to these systems. == 🧼 Regular Cleaning == The PET 4000 Series features a hinged metal chassis for easy internal acce..."