PDP 11/34 rebuild

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Tue May 13 19:31:22 2003

> Acquire a PDP11/34 system recently (11/34 CPU, RX02 dual drive, 2 off
> RL01 drives) ; before shipping it was running to the point of
> displaying an _at_ sign on the terminal happily (it didn't boot from DY
> as it should have but I thought I'd address that once it was back
> home).
>
> However, on putting it back together in my shed, the beast shows no

What did you dismantle for shipping? Is it possibly you forgot to plug
something back in inside the 11/34 power supply?

> front panel lights (not even DC OK), no LEDs on any cards & no _at_. The
> fans whir when powering on (

OK, so it's getting mains as far as the transformer.

HAve you checked the DC power supply rails at the backplane? That would
certainly be my first test.

> 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 (I may have some in
> the PDP11/44 system I have awaiting restoration)?

You do need grant continuity cards in the Unibus. In fact there are 5
grant lines -- 4 BG lines for interrupts and an NPG line for DMA.

There are 2 sorts of grant continuity cards. Single-height ones go in
slot D only, and connect the 4 BG lines. You have to put a wire-wrap
jumper between pins CA1 and CB1 on the back of the backplane for the NPG
line. Dual hight ones go into slots C and D and complete all 5 grants.


>
> Any pointers for what to check out & in what order?

(1) check the PSU!

-tony
Received on Tue May 13 2003 - 19:31:22 BST