Cleaning and Restoring a Badly Corroded PSU

Rob Jarratt robert.jarratt at ntlworld.com
Sat Oct 28 13:35:10 CDT 2017


Thanks Maciej,

 
>  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.


Your technique has to be better than mine because I used an iron, a suction
desoldering station and a flux pen. However, after multiple attempts
throughout the day, I finally succeeded a short while ago. I am not sure
what is wrong with my technique.


> 
>  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.


Indeed, there is no interference from the capacitor on that daughter board,
that didn't cause me 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).
> 

I will have to dig out the replacements I bought a while ago, I can't
remember what I chose, but I generally get the ones with higher
hour-temperature ratings.


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

I wish you luck with that! In my case I have not actually tried powering it
on yet, I really wanted to clean it up first as I am sure some of the bits
off the heatsinks were likely to create some shorts and I am pretty sure
some of these capacitors have leaked.

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?

Regards

Rob



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