18 Apr
2014
18 Apr
'14
1:51 p.m.
Ok, the schematics was very useful. It took me five minutes and an
oscilloscope to find the problem: the only capacitor. When I'm looking
back and checked how the capactior looked like from the start I should
have realized that that was the problem!
I also got a fast answer from Jack Rubin off list. Thanks to both of you!
/Anders
On 2014-04-18 21:07, Bob Vines wrote:
Message: 24
Date: Fri, 18 Apr 2014 10:26:05 +0200
From: Anders Sandahl <anders at abc80.net>
To: cctech at classiccmp.org
Subject: PDP-8a Power distribution box schematics
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
Is it the one shown in
http://z80cpu.eu/mirrors/oldcomputers.dyndns.org/rechner/dec/manuals/decima…
starting on PDF page 16?
Bob
