Switched power supplies

From: jpero_at_cgo.wave.ca <(jpero_at_cgo.wave.ca)>
Date: Mon Oct 6 12:34:23 1997

> Tony Duell wrote:
>
> > On Sun, 5 Oct 1997, Marvin wrote:
> >
> > > Take a look at the IBM tech reference manual as one of them (don't
> > recall
> > > which one, XT?) does has schematics for theirs. Also as far as trying
> > to
> >
> > Are you sure? _None_ of my IBM TechRefs (I have : PC, XT, AT (2 vols), O&A
> >
> > (2 vols), Scientific, EGA, PC-jr) have any PSU schematics at all. Well,
> > the PC-jr PSU card is there, as is the schematic of the professional
> > monitor PSU (the CGA monitor PSU is missing...).
>
> I just checked and it may have been that the Professional monitor PS was the
> one I used. From what I can remember (8 - 10 years ago), I had several IBM
> power supplies that needed to be fixed and I searched through my tech refs
> for a schematic. The one I found had an identical (or almost identical)
> front end (before the transformer) and that gave me enough info to fix the
> things.
>

I think: those XT power supplies in PC and XT series uses single
power transistor which is not used after the dual transistors type
since the AT power supplies, and it's not changed much since even in
clone ones as well.
Also, judge when cost is too much to fix when you can retrofit a
superior better quality power supplies out of PS/2 style PSU into the
orignal power supple shells, the fans IBM used is way out high
quality. Usually 10 percent out of dud power supplies I repair are
non-startable even after I find all the duds. Dunno why.

Having diffculty ordering the Bob's ESR meter because of being a
Canadian. Any suggestions?

Jason D.
Received on Mon Oct 06 1997 - 12:34:23 BST