Here are some schematic diagrams of the Commodore 64.


Commodore 64 cartridges
Disk drives
System firmware
Commodore 64 Service Manual in HTML format.
Service Manual, Model C64 Computer, Feb. 1985 PN-314001-02
Service and Tech Manuals for the C64
The portable variant of the Commodore 64


250469-rev.A-left.gif 2009-08-18 166347
250469-rev.A-right.gif 2009-08-18 134382
250469-rev.B-right.gif 2009-08-18 129880
Commodore 64c rev.A and rev.B (new design). The 64c boards have the following texts: PCB ASSY NO. 250469 and PCB NO. 252311 REV.A (or B on newer boards). The difference between the two revisions is in the Gate Array chip: The one in rev.B includes COLOR RAM. That is why only the right half of the schematic diagram differs. The REV.A schematics also has the part number 252312.
251138-1of2.gif 2009-08-18 296752
251138-2of2.gif 2009-08-18 291075
Commodore 64 schematic diagram 251138 from the Service Manual
251469-1of2.gif 2009-08-18 284360
251469-2of2.gif 2009-08-18 235530
Commodore 64 schematic diagram 251469 from the Service Manual
252278-1.gif 2009-08-18 267284
252278-2.gif 2009-08-18 230917
Commodore 64 schematic diagram 252278. This seems to be an intermediate cost-reduced version, with 64kbÃ4 memory chips but small ROMs.
252312-left.gif 2009-08-18 626038
252312-right.gif 2009-08-18 498353
A bit better scan of the 250469 REV.A, with 8 levels of gray.
326100.png 2009-08-18 524126
Commodore MAX Machine schematic diagram (also known as "VICKIE", VIC-10 and VC-10). The original was very noisy; the contrast was improved after scanning. In the scanning process, the top left and bottom right corners were omitted by mistake. The bottom right corner has been augmented.
326106-1of2.gif 2009-08-18 263850
326106-2of2.gif 2009-08-18 281339
Commodore 64 schematic diagram 326106 from the Service Manual
C64SchematicP1.png 2014-11-10 10745377
Page 1, based on schematic from ProgRefGuide - by Carsten Jensen
C64SchematicP2.png 2014-11-10 9905076
Page 2, based on schematic from ProgRefGuide - by Carsten Jensen
c64-cassette-io.gif 2009-08-18 24774
A block diagram of the Commodore 64 cassette I/O circuitry. Taken from the SAMS C64 Troubleshooting Guide.
c64-powersupply.gif 2009-08-18 31193
A block diagram of the Commodore 64 internal power supply (how the +12V, +9V and TOD clock signals are generated from the 9V AC input). Taken from the SAMS C64 Troubleshooting Guide.
c64-r1.chips.gif 2009-08-18 52036
A chip location diagram of the first C64 board revision. Assy number unknown, or maybe 251138. Taken from the SAMS C64 Troubleshooting Guide.
c64-video.gif 2009-08-18 22896
A block diagram of the video circuitry in the first C64 board revision. Taken from the SAMS C64 Troubleshooting Guide.
c64_external_power_supply_902503-02.png 2016-12-31 387640
PS Schematic based on William Levak's, with corrections by Dave Buchan
c64bus.gif 2009-08-18 29785
A block diagram of the bus signals in the C64.
c64extps.gif 2009-08-18 39589
Commodore 64 Power Supply, part no. 902503-02, input 116V 60Hz 40W. This is the North American power supply that can be taken apart. The schematic was drawn by William Levak. According to him, the transistor and the 300 ohm resistor can be removed and replaced with a standard +5V 750mA voltage regulator, which is much more reliable.
ciasid.gif 2009-08-18 86159
CIA and SID pinouts and general data
cpupla.gif 2009-08-18 89302
6510 and PLA pinouts and general data
maxschematic.jpg 2009-08-18 964251
Schematics of the Max Machine
mem.gif 2009-08-18 49415
2048k*8 SRAM pinout and general data. VIA pinout.
modulator-251025.gif 2009-08-18 120096
Modulator schematic 251025 from the Service Manual
modulator-251696.gif 2009-08-18 83802
Modulator schematic 251696 from the Service Manual
prg-cpu-left.gif 2009-08-18 196832
prg-cpu-right.gif 2009-08-18 117603
prg-vic-left.gif 2009-08-18 188463
prg-vic-right.gif 2009-08-18 174251
Commodore 64 schematic diagram, scanned with 360 DPI, 2 colours. This seems to be the same (buggy) schematic that was published in the Commodore 64 Programmer's Reference Guide, but has been partially translated into German.
The vic part contains the ROMs, SIDs, Video Controller, RAMs, Address-decoding, Expansion Port and User Port.
The cpu part contains the Port elements (CIA), CPU, AC-Adaptor, Timer, Port Layout
All resistors are 0.25W ±5% and all capacitors are in µF, unless otherwise stated.
ultimax.gif 2009-08-18 78504
Commodore VIC-10, a.k.a. UltiMax a.k.a. "Vickie" schematic diagram, drawn by Ruud Baltissen. For more information on this extremely rare machine, see http://www.funet.fi/pub/cbm/html/c64/ultimax.html. See also 326100.png.

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