Re: IIgs Monitor Repair

["Michael J. Mahon" <mjmahon@aol.com>]

ferdimh@gmx.de wrote:
> On Dec 27, 5:36 am, Polymorph <polymorp...@hotmail.com> wrote:
>
>
> > I had another idea anyhow, as I have another IIgs monitor that is
> > working OK, I thought I might try removing caps from it and use them
> > in the problematic monitor - trying one at a time until (*hopefully*)
> > the problem goes away. That way I should be able to isolate the
> > problem cap and replace only it. It will involve more work, but might
> > be the best way of debugging the problem? Again, experts thoughts are
> > welcome - I'm most definitely out of my comfort zone (please remember,
> > I'm a software guy, cutting his teeth in hardware) and I'm mostly
> > winging it with educated guesses.  :-)
>
>
> There is a simpler trick: get a  tool that allows  to heat or cool the
> caps. This could be:
>  - a hair dryer or heat gun
>  - your soldering iron
>  - a candle or a lighter/matches if used with care
>  - cold spray
> try to heat/cool any suspect cap and see if the problem changes.
> If it does, you found a bad cap.

Unfortunately, this only works when the monitor is working well
enough to be able to observe changes.  Temperature changes will
hardly ever restore function to a dried-out electrolytic.

It can be quite effective for potentially (electrically) leaky
non-electrolytic capacitors, and for any thermal intermittent.

Bridging electrolytics with a suitable test capacitor is very
effective at isolating failing capacitors.

-michael

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Home page:  http://members.aol.com/MJMahon/

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