11 May
2006
11 May
'06
6:44 p.m.
Disregard this, I didn't have it on the wrong side. I was viewing the
diagram wrong.
I forgot that the diagram says the H754/784 AC input connectors are white :p
-----Original Message-----
From: cctalk-bounces at classiccmp.org
[mailto:cctalk-bounces at classiccmp.org] On Behalf Of Julian Wolfe
Sent: Thursday, May 11, 2006 7:13 PM
To: 'General Discussion: On-Topic and Off-Topic Posts'
Subject: RE: BA11-K low AC output levels
You're right. Somehow when I reassembled the power supply
when I wasn't testing it (just put it back together to move
it out of the way)I put the
H745 in the WRONG SIDE. Therefore, I have it now hooked up
to the battery backup plug.
Duh, duh, and, more duh. :p
Needless to say I'm going to be starting all over when I get home.
Thanks for all your help in my chasing shadows.
Julian
OK. Converting one to the other is possible, in that the
metal frame is the same apart from the markings on it. But
there are several internal wiring changes, I think the little
intenral transformer and the contactor are replaced, etc. I
don't think it's likely this has happened.
You could try looking at the wiring to the socket where the
transformer primary is connected (IIRC this is a 4 pin
connector on the front side of the input box). Does it look
as though the windings are in parallel (wires from the
contactor each go to 2 pins on that connector), or in series
(wires from the contactor go to 1 pin each, the remaing 2
pins are linked but not connected to anything else)? The
former is 115V, the later 230V.
-----Original Message-----
From: cctalk-bounces at classiccmp.org
[mailto:cctalk-bounces at classiccmp.org] On Behalf Of Tony Duell
Sent: Thursday, May 11, 2006 6:34 PM
To: cctalk at classiccmp.org
Subject: Re: BA11-K low AC output levels
It'll light
Tony, responses to your statements are below, but as a general
question to those who are helping me with this, is the H745 light
supposed to come on if it's just connected to the power
distribution
board? i.e. am I supposed to se a light on with
no load
like the H7441s do?
Yes, you are. The lamp is simply connected across the output of the
regulator -- that is between the output line and ground. up if the regulator is working.
wire at a time.
That might well explain it.
Try measuring the AC voltage between the 2 wires at each regulator
labelled '20-30V AC'. That is, connect one lead of your
voltmeter to
Now, you
should see 20-30V _between the 2 wires going to a
particular regulator_. Not between either wire and earth.
This could explain my reading. I was only measuring one one of the wires, the other lead to the other
wire.
20-30V AC
Not that it matters, but the thing that got me
started on
this path is
that the H745 has two pins, who each say
"20-30VAC"
Yes, it's somewhat confusing. It means you need to connect between those 2 pins. The printset should show
how the
transformer is
connected (note that there are no connections to
the secondary
windings other than to these regulator bricks, there are no
grounds,
no taps connected to ground, etc). And the prints
of the regulator
should justify _why_ you connect it like that. From what I
remember,
those to pins go to the AC terminals of a bridge
rectifier,
the output
of which goes to a large smoothing capacitor. And
at least
for the +5V
brick, one side of that capacitor is then
grounded.
> > contactor and its control supply. Is it possible that
you have a
230V unit plugged into a 115V mains socket?
I highly doubt this as the AC input box is clearly marked 120V. Wow, OK, so what is it then? This really has me
stumped.
Is it still possible I have an input box problem?
See above. I don't think there's anything wrong with the PSU
at all. Just that you're not measuring the voltage you think
you're measuring.
-tony