--- Greg Elkin <ClassicComputers_at_bouncy-castle.demon.co.uk> wrote:
> Acquire a PDP11/34 system recently... before shipping it was running..
> ...on putting it back together in my shed, the beast shows no
> front panel lights (not even DC OK)... The fans whir when powering on
Hmm... How far did you dismantle it for shipping? Did you haul it
or did you leave it in the hands of a common carrier?
> If I want to take out the RL01 & RX02 controllers & the unknown card
> in slot 6, do I just leave the cards out (I'm a QBUS guy, don't know
> much yet about UNIBUS and any daisy chaining DMA/INT signals etc) or
> will I need some grant controllers of some form
Just like the Qbus, the Unibus has several signals that need granted.
More, in fact. If you know that the NPR jumper is in place (i.e., it's
an empty slot or had a *non-DMA* peripheral), you can use a G727 single-
height grant card. If you pull a DMA peripheral (RL11, for sure, probably
the RX211 as well), you must either install a dual-height grant card
(G7273 or a Software Results GC747) _or_ put the NPR wire back on the
backplane and use a G727.
Now... the "good" news is that this only affects interrupts and DMA
requests. AFAIK, console ODT (the '_at_' prompt) has nothing to do wth
interrupts. You should be able to stuff the CPU, a DL-11 and little
else (probably a bus terminator at the end of the CPU backplane, and
maybe some memory) and get the prompt when you power on. First order
of business, though, is to check your voltages. The fact that you have
no DC OK light is a blatant symptom. It could be because of a short,
or perhaps something got rattled loose in a PSU during shipping.
Investigate the PSU fully before moving onto the cards. Reduce
your system to the system backplane only (if you have any DD11-DKs or
the like). Look into the backplane slots themselves with a flashlight
(for a washer or other conductor that might have dropped in there).
Check the back of the backplane for any bent pins that might be causing
a short. Disconnect the backplane from the PSU and check it for shorts
electrically.
-ethan
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Received on Tue May 13 2003 - 08:56:00 BST