Cleaning and Restoring a Badly Corroded PSU

[Rob Jarratt]

I have ordered the part now anyway. Whether I will replace it or not I don't
know yet. I am told that ESR measurements are not enough to detect bad caps
though, although I always replace ones with ESR that is at or close to the
limit on the table printed on my meter.

Regards

Rob

> -----Original Message-----
> From: Maciej W. Rozycki [mailto:macro at linux-mips.org]
> Sent: 30 October 2017 12:12
> To: rob at jarratt.me.uk
> Cc: 'General Discussion: On-Topic and Off-Topic Posts'
> <cctalk at classiccmp.org>; 'dwight' <dkelvey at hotmail.com>
> Subject: RE: Cleaning and Restoring a Badly Corroded PSU
> 
> Hi Rob,
> 
> > By the way I just noticed a 15uF/25V one next to the fan connector. It
> > isn't one of the SXF ones as far as I can tell, do you recall replacing
it?
> 
>  My notes indicate it is a Chemi-Con SM, a general purpose 85°C part.  I
did
> replace it at least once, in one of my H7826s that didn't actually get to
leaking
> (yet?) and was still in a working condition.  I suspect doing the
replacement
> didn't really matter, as measuring the original gave reasonable readings
for its
> class.
> 
>  I also have a later revision of H7826 which has LXF rather than SXF
capacitors
> and this one looks really clean, almost like new, and also works
correctly.  I am
> in two minds about recapping this one, because despite of the good shape
of
> the PSU my sources indicate the LXF parts have also suffered from the
> quaternary ammonium salt syndrome.  I'll yet check the ESR for any
suspicious
> raise.
> 
>   Maciej