There were two major versions of the Atari PC3 Motherboard during it’s lifespan. It originally came with the C100812 produced in 1988 and followed by the C103272 in 1989, the last year of the Atari PC3’s production. Besides the different PCB colour, the major differences between the two was the EGA chip which was used. The C100812 used the NSI Logic EVC315 where as the C103272 changed to the STMicroelectronics EGA Chipset and was designated the Atari P/N C101702-001. Testing under Landmark System Speed Test Version 6.00 tends to suggest performance was not a consideration with the change in chip as both recorded similar speeds (466.34 chr/ms for the NSI Logic vs 465.45 chr/ms for the STMicroelectronics).
Within these two versions there was often a Revision “B” and Revision “B1” of which the changes were relatively minor. However just to confuse things, I have seen examples of minor changes occurring across the same revision motherboard that were only built weeks apart. For example, the C100812 Rev.B1 seen on this page was manufactured just 3 weeks after the one I have and appears identical except that the 8250 UART chip on that particular motherboard is soldered directly to the board whereas the example I have is socketed.
Click on an image below for closer look at the boards.
|C100812 Revision B (1988)||C100812 Revision B1 (1988)||C103272 Revision (Not Designated) (1989)||C103272 Revision B (1989)|