30 Apr
2011
30 Apr
'11
1:47 p.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Tony Duell
Sent: 30 April 2011 19:56
To: cctalk at classiccmp.org
Subject: Re: H7140 PDP11 PSU
is
When I was looking at Bias and Interface board I
realised that the +5V
must indeed be coming from elsewhere as the tracks are not even
connected
(directly) to the PSU motherboard. As you suspected, the output of E1 is
0V.
Well that certainly expalins why the relay isn't firing, and why the PSU dead (no power to a lot of the control logic).
What is the input to E1 (the 7805)? My guess is 0V again, which means we
have to do battle with an SMPSU (and one where a lot of the circuitry is
directly connected to the mains). On the other hand, it's worth checking
in
case you're lucky and it's just the 7805
that's failed.
Incidentally, where are you based? I assume from the terms you use that
you're in the UK.
Manchester. From what I recall from earlier emails you are in London,
correct?
-tony