Subject: Re: Dying 3100 power supply
To: None <>
From: Anders Hogrelius SdU <>
List: port-vax
Date: 02/22/2000 00:08:03
On Mon, 21 Feb 2000, =DE=F3r=F0ur =CDvarsson wrote:
> As electronic tecnician I would recomend following
> disassemble the psu
> clean, blow, vacuum all dust,bugs and ... from the unit
> examine the solder side of the PCB board, carefully examine all solder
> drops to see if there are any cracks, very very fine cracks are trouble
> to.
> re-solder the cracked solder spots

Take special care to examine the solder at the power semiconductors,
like the switch transistor and the rectifiers. That's where the cracks
are most likely to occur, together with the solder at the
switchtransformer and the high frequency chokes. Even if the solder
looks good, the cracks can be to small to see with the naked eye,
so, if in doubt, -solder.

If the problem still occurs, check the switch transistor, sometimes
a crack develops inside, and is nearly impossible to find even with
an instrument. The best way then is just to replace it, if you can
find a replacement, it's usually quite cheap so the best way is
often just to replace it and see what happens.=20



 -Microsoft is NOT the answer, Microsoft is the question.
 -The answer is NO!!!

* Anders Hogrelius SdU   Phone : +46 21 381860  =20
* Tessingatan 12         E-mail:        =20
* 72216 Vasteras                       =20