PDP-8a Power distribution box schematics - test-drb@ccmp.vtda.org

18 Apr 2014

Hi there,
I've seen a similar problem and have a schematic that I can send you in a day or two
when I get to it. It may be due to leaky cap on the back panel because the relay is
actuated by 5v that oscillates.
Shaun

Sent from my T-Mobile 4G LTE Device

<div>-------- Original message --------</div><div>From: Al Kossow
<aek at bitsavers.org> </div><div>Date:18/04/2014  7:29 PM  (GMT-06:00)
</div><div>To: cctalk at classiccmp.org </div><div>Subject: Re:
PDP-8a Power distribution box schematics </div><div>
</div>On 4/18/14 1:26 AM, Anders Sandahl wrote:
...
  Hi,

 I'm looking for the schematics to the power distribution box that use to sit in the
bottom of the rack. I have browsed bit-savers.org but I don't know where too look. Can
anybody give me a clue?

 http://www.abc80.net/docs/pdp8/pdp8a/DSC_2287.JPG
 http://www.abc80.net/docs/pdp8/pdp8a/DSC_2291.JPG

 Problem for this one is  when putting the switch in local mode the big relay (contactor?)
 is activated, bit after a white it starts to jumps between activated/deactivated. I
measured the voltage over
 the coil and it decreased rapidly when it happens.  The contactor is tested standalone.

 I have cleaned this up and repainted it, but have no pictures after the refurbishment.

 /Anders

 DEC-00-H861A-A-D 861-A,B,C Power Controller Maintenance Manual.pdf