8640 looks like a date code; most dec chip numbers begin with "DC".
On 10/28/18, 6:53 PM, "cctalk on behalf of Rob Jarratt via cctalk" <cctalk-boun...@classiccmp.org on behalf of cctalk@classiccmp.org> wrote: I am trying to trace the reason why the CPU on my Pro 350 is apparently being constantly reset. I have reached a DEC 8640 chip. Does anyone have a pinout for it, perhaps even a datasheet, so I can understand what it is supposed to do and whether the pin is an input or an output? Thanks Rob