On Sun, Oct 28, 2018 at 5:53 PM Rob Jarratt via cctalk <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? >
I've sent the data sheet by private e-mail. Have you looked at the Pro380 printset on bitsavers? The reset input on the J11 chip in that machine comes from the DCOK pin on the power supply (Pin 1 of the PSU connector). It's also buffered by an 8640 for other bits of the systen. I would not be surprised if the Pro 350 is similar. Are you_sure_ the DCOK pin on the power supply is stable and not oscillating? -tony
