1 Sep
2014
1 Sep
'14
8:11 a.m.
-----Oorspronkelijk bericht-----
Van: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org]
Namens Simon Claessen
Verzonden: maandag 1 september 2014 11:31
Aan: cctalk at classiccmp.org
Onderwerp: HP 150 power supply
Hello all
Since we got 4 of them, allw ith a broken power supply, I was wondering if
someone has already stumbled upon a solution. i have not open them yet, but i
think the problems are the same on all of them. googling on
hp150 is not the way to go unless you want info for modern devices having 150
in their names...
--
Met vriendelijke Groet,
Simon Claessen
drukknop.nl
Simon,
The PSU aren't very complicated, most likely there's a shortcut on the secondary
side.
Check the rectifiers and elco's on the low voltage side, I've had 2 PSU's with
a shorted 12V rectifier.
They won't start then because the over current protection will prohibit the startup of
the PSU.
Next thing to check is the high voltage rectifier and elco's you should measure about
325V DC after the rectifier after that check the high voltage switching transistors for
shorts.
IIRC the regulator is built from normal op-amps LM339 etc.. and not really suspected,
rectifiers elco's and switching transistors are more likely to fail.
Be careful the 325V is deadly, of possible use a safety transformer when the PSU is
plugged in.
-Rik