Cleaning and Restoring a Badly Corroded PSU

[Rob Jarratt]

> -----Original Message-----
> From: Maciej W. Rozycki [mailto:macro at linux-mips.org]
> Sent: 28 October 2017 18:48
> 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
> 
> On Sat, 28 Oct 2017, Maciej W. Rozycki wrote:
> 
> > > 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.
> 
>  On second thoughts if solder has corroded, which may well be the case
given
> the overall state of your PSU, then you will have troubles melting it,
because,
> obviously, oxides and other compounds which would have formed won't
usually
> melt as easily as metal.  In that case I suggest trying mechanical means
to
> remove the contamination and then applying extra solder to increase its
mass
> in the joint before trying to undo it.
> 

Yes, I did the extra solder thing too, the problem there was getting it to
flow properly, even with extra flux from a pen. I couldn't get much new
solder into the joint. I never thought to remove the contamination though,
which is probably part of the reason why the extra solder would not flow,
one to remember next time.

>  I do remember having problems with handling corroded joints next to
leaked
> capacitors in my H7874 PSUs, even though those specific joints didn't have
any
> way to lose heat easily.
> 
>  HTH,
> 
>   Maciej