wiped disk - no longer bootable

[Mike Marchywka]

On Wed, Jul 10, 2019 at 11:45:05AM +0200, Ralf Mardorf via ubuntu-users wrote:
> On Wed, 10 Jul 2019 07:56:20 +0000, Mike Marchywka wrote:
> >On Wed, Jul 10, 2019 at 09:08:35AM +0200, Ralf Mardorf via
> >ubuntu-users wrote:
> >> On Tue, 9 Jul 2019 19:08:21 -0400, Gene Heskett wrote:  
> >> >That mobo was simply not repairable because my hot air tools were
> >> >burning the foil off the board on one side while trying to telegraph
> >> >enough heat to the other, inaccessable side of the board to free the
> >> >defective caps.  
> >> 
> >> It's possible to heat both sides, unfortunately the VIAs of
> >> multilayer PCBs tend to be allergic to too much heat, so it's a game
> >> of pure chance.  
> >
> >Did these guys go lead free or you know the alloy/ melting point?
> >How hard is it to get to both sides?
> >I guess you could hack up the caps, maybe just with pliers,  leaving
> >just wire and through the holes but that would be a huge mess. Then
> >just grab the remaining wire with needle nose pliers and
> >pull it while heating.  
> 
> The heat isn't evenly spread. Even if you try to vacuum of the solder
> with a professional unsoldering station, you probably would pull the
> remaining wire and the VIA or as Gene already mentioned, you burn the

Unsoldering a ground plane may be a problem but it gets worse if the
melting temp of the solder has increased- curious what
they wave solder these days. Eutectic Pb/Sn would be great but
the new alloys may even have issues with their interactions
with the board metal- maybe making them more prone to rip on
desoldering. For that matter maybe even the flux chemistry matter.
Even with tight tolerances the facotry inserted leads should be
pretty straight and allow solder to flow in and then pull the thing
out. 
I guess if it is a really odd solder chemistry maybe there is a
selective etch that won't wreck everything nearby. 

> PCB and you might damage the conductor path. I tried to solder out
> borked caps of my mixing console's SMPS with my less good equipment, a
> friend tried at home with a professional unsoldering station from
> Weller, it didn't work. At work the friend could use very good
> professional hot air equipment and he was able to replace the caps, but
> it wasn't easy to do.
> 
> 
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mike marchywka
306 charles cox
canton GA 30115
USA, Earth 
marchywka at hotmail.com
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ORCID: 0000-0001-9237-455X