HOW TO IDENTIFY YOUR C64 BOARD
              latest updates and corrections 9-11-14

     There were half a dozen basic versions of the Commodore 64 and several
minor revisions of some motherboards. The earliest boards had a cardboard 
and tinfoil shield. To find out what board you have, the keyboard top cover 
must be removed (three Philips screws) and the cardboard shield folded back 
to see the ID number on the lower edge of the board. You can remove and 
discard that cardboard shield. Note: this early board has a five pin DIN
A/V connector; all the later boards have an eight pin jack with S-video. 

326298, schematic 326106 was the first Commodore 64 production motherboard. 
It had an early version ceramic VIC chip that produced vertical "ghost" lines 
after all characters. This board also has a weaker than normal video output 
which is a factory error. See the article in the 326298 directory for 
instructions how to correct it. 

250407, schematic 251138 is the most common and apparently the most plentiful 
board. There are several revisions but the basic design is the same. Many 
boards used the original ceramic VIC (see above) which can be replaced with 
the newer black epoxy case 6567 VIC for cleaner video output. 

250425, schematic 251469 is a later board with fewer chips for cost reduction. 
It's the first board to use a single 8701 clock generator IC to replace four 
IC's used in the previous designs. This is the first board to use a metal 
shield with "fingers" which act as heat sinks for the chips that run hot 
normally such as the PLA and SID. All later boards have this metal shield. 
Some may have the early ceramic VIC chip. (see above)

250441, schematic 251469 note: this board never went into production.

250466, schematic 252278-1 is an interim board that further reduced the parts 
count. It has only two 4464 RAM chips instead of the eight 4164 chips used in 
the earlier boards. 

250469, schematics 252312 and 250469. There are two similar versions of this
last C64 "short" board, hence two schematics. They feature a later 85xx 
"family" of ICs which are generally not interchangeable with earlier chips. 
It has the lowest parts count of any C64.