Cleaning and Restoring a Badly Corroded PSU

Maciej W. Rozycki macro at linux-mips.org
Sat Oct 28 12:26:59 CDT 2017


Hello Rob,

> That 4700uF/10V capacitor is really hard to remove, it seem to be connected
> to large planes on both sides, which suck all the heat away. I have a
> suspicion that it may have leaked from the underside as the area around it
> is certainly quite dirty in a way that suggest the dirt has stuck to
> something.
> 
> Did you manage to remove this part without destroying it and without
> damaging the board?

 Yes, in all cases.  I didn't recall any issues with unsoldering this part 
really, using a simple 40W iron and desoldering wick only, and extra flux 
from a pen.

 Getting the part out once unsoldered was in my case a bit tricky once or 
twice because of the daugthercard sitting next having a 220uF/16V KMC part 
on the daugthercard blocking the 4700uF/10V from the above, but it was 
eventually doable with some manoeuvre; their position WRT each other seems 
to vary a bit between individual H7826s and from your photo I infer you 
have one where this won't be a problem.

 BTW I chose a Panasonic FR as a replacement (Farnell has them), leaving 
considerably more space around (make sure you pick the right diameter if 
you choose this part too, as there are two variants at this capacitance 
and voltage).

 Unfortunately lone recapping didn't fix my worst leaked H7826s, I yet 
need to track down what else has failed. :(

  Maciej


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