H744 +5 supply - easy to fix?

From: Pete Turnbull <pete_at_dunnington.u-net.com>
Date: Thu Mar 4 02:07:19 2004

On Mar 4, 8:22, Gooijen H wrote:

> I repaired 2 H744's up till now.
> They are indeed an easy piece to work on.
> One had a defective rectifier bridge (the 1 x 1 inch square
> block with 4 terminals) and the other was more peculiar:
> one big electrolitic capacitor (AFAICR it is connected
> directly to the PCB, fixed with screws) made a short circuit
> between the housing of the capacitor and a trace on the
> board. The plastic insulation of the capacitor some how was
> that bad to allow the short circuit ...!

Hmmm... one of mine had a faulty rectifier too. Not hard to diagnose
or replace, but I wonder if that's a common failure? Another one had a
bad filter cap -- but it had died of age (leaked) rather than causing a
short. Another common "problem" seems to be whistling from the coil,
if it's begun to delaminate. Probably a sign of previously running
hot, and not necessarily anything to worry about. Several of my
"brick" PSUs had faulty bulbs, and I found the easiest way to fix that
ws to replace the bulb with an LED and a resistor, as found on the
later versions.

Pete						Peter Turnbull
						Network Manager
						University of York
Received on Thu Mar 04 2004 - 02:07:19 GMT

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