PDP 11/70: MK11 memory crate, M9312 cards, and wiring...

From: Jules Richardson <julesrichardsonuk_at_yahoo.co.uk>
Date: Sat Oct 16 12:29:53 2004

On Sat, 2004-10-16 at 09:22 -0400, M Thompson wrote:
> >Heh - I was staring at DEC engineering drawings for hours and it was
> >giving me a headache! I need to look at all the info for the memory
> >crate though as the CPU still isn't happy (the run lamp's permanently on
> >and we can't halt the CPU or toggle any data in from the front panel).
> >All cards look to be OK in the CPU though, but I suspect there may be a
> >problem with the memory...
> I have seen the same problem with 11/34 systems when the bus grant and
> interrupt daisy-chain was broken in the backplane. Are there any empty
> Unibus slots? Did you check that the wire-wrap jumper is in place in the
> non-DMA device slots?

Thanks - we gave the bus a quick once-over and it looks OK, but I'll
have another look and really sit and stare at it. The cards *should* be
back in the places they were at when the system was last run, but I'll
triple-check it :) Interesting point about the jumpers; that's
something I haven't looked at at all - again it *should* be OK, but
maybe something's worked loose in getting the machine into storage ten
years or so ago and more recently when it was all pulled back out


Received on Sat Oct 16 2004 - 12:29:53 BST

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