Commodore 64 / 64C Service Manual
The Service Manual C64/C64C, March 1992, part number PN-314001-03, is Commodore Business Machines, Inc.'s own 57-page service manual for the Commodore 64 and Commodore 64C. It is the last edition Commodore published, and the primary service reference for both machines on this wiki.
It carries component-level parts lists for every mainboard revision — 326298-01, 250407-04, 250425-01, 250466-01 (C64-B3) and 250469-01 (C64-E) — giving capacitance, voltage rating, tolerance, package and Commodore part number for each capacitor. It also contains Commodore's own troubleshooting guide, a symptom-to-component table of roughly thirty faults, and the board-revision-to-model cross-reference.
It is the source for the component values on Commodore 64 Capacitor Replacement Guide and Commodore 64C Capacitor Replacement Guide. Both pages previously carried values that appear in no Commodore parts list; they were rebuilt from this manual in September 2026.
The scan carries a text layer.
Board revisions covered
edit| Revision | Assembly | Notes |
|---|---|---|
| Original | 326298-01 | 5-pin video connector, "long board" |
| A (CR) | 250407-01 / -04 | 8-pin video connector, long board |
| B | 250425-01 | Long board, cost-reduced |
| B3 | 250466-01 | C64-B3 |
| E | 250469-01 | "Short board" — also used in the Commodore 64C |
Contents
edit| Title | Page |
|---|---|
| Specifications | 1 |
| Product parts list | 2 |
| Block diagram | 3 |
| Circuit theory — power supply, reset logic, clock circuits | 4–6 |
| Circuit theory — I/O, ROM, expansion port; RAM control logic | 7–8 |
| Circuit theory — 5-pin and 8-pin video and audio outputs | 9–10 |
| Circuit theory — cassette interface; keyboard, joystick and paddle interfaces; serial interface and user port | 11–13 |
| Troubleshooting guide | 14 |
| Board identification | 17 |
| PCB assembly 326298-01 — layout, parts lists, pin assignments, schematic 326106 | 18–22 |
| PCB assembly 250407-04 — layout, parts list, modulator schematic 251025, schematic 251138, pin assignments | 23–27 |
| PCB assembly 250425-01 — layout, parts list, modulator schematic 251696, schematic 251469, pin assignments | 28–32 |
| Service reference diagram B-3 | 33 |
| B-3 PCB parts list | 34 |
| B-3 board layout | 36 |
| B-3 schematics 252278 | 37 |
| Service reference diagram E | 39 |
| E PCB parts list | 40 |
| E board layout | 41 |
| E schematic 252312 | 42 |
What this manual settles
edit- It is the only document on this wiki that carries the B-3 and E boards. Pages 33 to 42 — the service reference diagrams, parts lists, board layouts and schematics 252278 (B-3) and 252312 (E) — exist in this edition and in neither 1985 edition. Every figure on Commodore 64C Capacitor Replacement Guide for the short board traces to the 250469-01 (E) parts list on page 40 and to schematic 252312.
- Board identification comes before any parts list. Page 17 is what tells a reader which of the five assemblies is in front of them; a value taken from the wrong assembly's list is simply wrong, and the assemblies differ.
- The 1985 editions do not supersede this one and are not superseded in content. Commodore 64 Service Manual (1985 Mar) and Commodore 64 Service Manual (1985 Sep) (both PN-314001-02) carry the same three early assemblies; this edition carries those three plus B-3 and E.
What this manual does not contain
edit- No power supply brick internals. The circuit theory section covers the on-board supply only. The external C64 supply — the part that fails and takes the machine with it — is not documented here; see Commodore 64 Power-Supply Protector (C64 Saver).
- No 1541 or peripheral coverage.
- No keyboard assembly parts list below assembly level.
Download the Commodore 64 / 64C Service Manual here: Commodore 64 - 64C Service Manual.pdf
Other Commodore 64 service documentation on this wiki
edit- Commodore 64 Service Manual (1985 Feb) · Commodore 64 Service Manual (1985 Mar) · Commodore 64 Service Manual (1985 Sep) — earlier revisions. The "1985 Feb" page holds the same file as the "1985 Mar" page; there is no February document here.
- Commodore 64 Diagnostic Instruction and Troubleshooting Manual (326070-01) — Commodore's diagnostic cartridge documentation
- Commodore 64 Technical Manual and Parts List — P/N 990439, the drawing package: drawing tree 326101, the 250407 rev B parts list and schematic 251138
- Commodore 64GS Technical Data (400401-01, 1990 May) — the Games System, assembly level only