The voltages are correct even with a half-fried transformer. Sounds
like typical HP overdesign. :-)
Did you check for ripple or noise on the outputs?
I'm intrigued by the fact that the error message is pointing you towards
the Outguard Controller, but the only apparent damage is to the Inguard
Power Supply. Could the error message be a red herring? Could the
actual damage be in the Inguard Section as shown in Fig. 28 (p. 70) of
the Assembly Level Repair Manual? This would at least be consistent
with damage to the Inguard Power Supply. But it seems odd that HP would
have such a misleading error message.
Does the error change if the fiber links are disconnected? Can you
probe the optical receivers with a scope to see if there's data on the
links?
Ed
Brooke Clarke wrote:
Hi Ed:
Yes, all the supply voltages are within spec, but the error message
stays the same.
The Outguard supply visually looks OK and the voltages are centered in
the spec.
Yes the transformer has seven wires feeding the outguard p.s.
See: http://www.prc68.com/I/HP3458DVM.shtml#Bot
You may need to <shift><reload page> to see it.
Have Fun,
Brooke Clarke
http://www.prc68.com
Ed Palmer wrote:
You're right. Sorry.
Brooke, now that you know the source of at least this problem, have
you considered powering up the system by applying DC to the inputs of
the regulators? This would allow you to limit the current in case
there's been some damage further in.
Also, is the Outguard p.s. connected to the same transformer? I
would expect to see a similar circuit topology on both supplies. Is
there any heat damage on the Outguard p.s.?
Ed
J. Forster wrote:
Look at the Ohms readings. It's not open, if the readings are right.
-John
=============
Try putting a light load on the transformer when you measure the
output
voltage (maybe 1K). You may find that terminals 2-3 are open circuit
rather than short. Maybe that's why CR10 survived - the transformer
blew first.
Ed
Brooke Clarke wrote:
Hi John:
It's hard to say. With the A4 Inguard p.s. board removed when
powered
up the fan comes on and the display lights up with the error message.
So, measured on the primary side, there's 25 ma AC current going to
the transformer then to the Outguard p.s. and fan.
Have Fun,
Brooke Clarke
http://www.prc68.com
J. Forster wrote:
Looks like it. Does the transformer draw much current with the PCB
removed? If it has shorted turns, as it appears, it likely will.
Does
it
get hot?
-John
=================
Hi:
I think the power transformer got cooked. Have a look at the Vac
and Ohms
data: http://www.prc68.com/I/HP3458DVM.shtml#T1
Force a browser refresh to see the latest schematic.
Have Fun,
Brooke Clarke
http://www.prc68.com
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