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The Commodore 128 existed in three different major board versions: The first board was used in the flat 128 and in the plastic-cased 128D. Then came the 128DCR board, with the floppy controller integrated on the motherboard. There was also a 128CR (cost-reduced flat 128).


Disk drives
System firmware
Power supply schematics
Service Manuals for C128-based computers


310378-1-left.gif 1996-11-27 118674
310378-1-right.gif 1996-11-27 113712
310378-2-left.gif 1996-11-27 99301
310378-2-right.gif 1996-11-27 107805
310378-3-left.gif 1996-11-27 130766
310378-3-right.gif 1996-11-27 77337
310378-4-left.gif 1996-11-27 99507
310378-4-right.gif 1996-11-27 90149
These are the schematic diagrams of the Commodore 128 main board
("flat C128" and C128D in plastic case). They were on eight pages
in the Commodore 128 Programmer's Reference Guide, two pages
containing one engineering sheet.

310378-update.zip 1998-05-15 747229
Update to the Commodore 128 Service Manual, containing the two revised
pages in the 310378 schematic revision 7A.

8721-pla.v 2022-01-05 10319
8721 PLA in Verilog by Johan Grip

c128cr.jpg 2000-02-23 1115174
A black&white picture of a cost-reduced flat Commodore 128 circuit board.
This model never entered mass production; this is an engineering sample
possessed by Raymond Carlsen. The board says "PCB ASSY NO. 250783",
"C= commodore C128CR REV.3", "PCB NO. 252270", and "C128CR No.2
ENG. SAMPLE Jun/9/'86 KNT".

c128dcr-1-left.gif 1996-12-13 172416
c128dcr-1-right.gif 1996-12-13 90870
c128dcr-2-left.gif 1996-12-13 143437
c128dcr-2-right.gif 1996-12-13 148206
c128dcr-3-left.gif 1996-12-13 128384
c128dcr-3-right.gif 1996-12-13 134398
c128dcr-4-left.gif 1996-12-13 77902
c128dcr-4-right.gif 1996-12-13 58823
c128dcr-5-left.gif 1996-12-13 126315
c128dcr-5-left_and_right_corrected.gif 2020-10-19 2128158
Corrected and combined c128dcr-4 and 5.

c128dcr-5-right.gif 1996-12-13 144315
These are the schematic diagrams of the Commodore 128DCR main board
(metal case C128D with built-in 1571CR floppy controller). The diagrams
were scanned from a 64'er Sonderheft, and they appear to be a copy of
schematic 252451.

According to Nicolas Welte, there is an error on the right half of page 5.
The 74LS14 hex Schmitt-trigger inverter U113, pin 13 is connected to WPRT*
(misprinted WTRT* on U105), which doesn't make any sense. Obviously it
should be connected to STP1 instead, which is three lines more to the right!

c128schematic.gif 2018-05-17 752001
C128 schematic, unknown rev, drawn by unknown author.

mainboardC128_rev7.png 2019-11-04 12004815
Hi-res picture of 128 main board traces, without chips.

parts.txt 2015-07-08 1830
Parts list for Commodore 128, from William Levak

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