Switching supply expertise?

From: Geoff Reed <geoffr_at_zipcon.net>
Date: Mon May 31 01:13:02 2004

speaking of kaypros I may have a couple available shortly, they are in my
garage and I need to see which ones work and are complete I'm probably
keeping one of them.

At 05:33 PM 5/30/2004, you wrote:
> > >> I'd buckshot the components in the switch driver, such as the
> IC. Sounds
> > >
> > >In a supply of this age, I would not be suprised if the chopper driver
> > >was discrete transsitors.
> >
> > It is - the only IC is the Opto-isolator.
>
>What, not even a TL431 in the secondary-side regulator? That does suprise me.
>
> >
> > Anyway - I found the problem - It was a shorted capacitor on the
> primary side
>
>Well done!
>
> > of the transformer - what threw me off was it was NOT one of the
> electrolytics...
> > There's another one beside it which is just like it, so I think I will
> replace
> > both.
>
>Maybe part of the snubber network on the primary of the chopper
>transformer. In which case, check the associated diodes too.
>
> >
> > Supply works fine now - and so does the entire machine.
> >
> > (Joy at getting an old Apple clone working somewhat overshadowed by the
> fact
> > that I finally found a Kaypro today!)
>
>I really must find a CP/M luggable sometime....
>
>-tony
Received on Mon May 31 2004 - 01:13:02 BST