PDP-11/34a hung bus problem.

E. Groenenberg ed at groenenberg.net
Mon May 16 11:13:32 CDT 2016

A little progress on the 11/34a

I have a PMK05 (Unibus exerciser) of which I forgot I had it.....

I checked it out first and noticed that the aluminum casting around the
4 slot backplane was broken on both sides. After repairing it by making
2 sleeves of thin copper sheet and a cobblers hammer it became strong
enough to insert the cards again.

After hooking up the PMK05 to the unibus, the machine was powered up
with the memory card, and the 'NPG' led was on.

When done without the memory card, the NPG led stayed off, and others
came on.

The address & data leds changed after depositing a character in
the transmit buffer of the DL11-W.

Pics at www.groenenberg.net/download/PDP11/pic for thos who want to
see the PMK05 in action.

(BTW, the unibus in and out are misprinted on the silkscreen and are

BTW2, is there someone who has a manual for it? I only have 2 (xeroxed)
pages of information.

Ik email, dus ik besta.
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