DEC 8640 Pinout

[Tony Duell]

On Sun, Oct 28, 2018 at 5:53 PM Rob Jarratt via cctalk
<cctalk at 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