All,
I always wondered why the C8 - 100uf cap on the +5V supply line only
had > a > > 6.3WVDC rating..... cost? size??? I used a 25WVDC replacement.
TIP(1) - Since I did not really care about the condition of the
'original' caps on the A9 board, I did a 'distructive removal' ....
to make the cleaning of the PC board holes easier, and to also
prevent overheating the PC board, from trying to remove the old caps
(which really are just large heat sinks, when trying to unsolder them
from below).
This is an old 'US Navy electronics repair depot' trick: To remove
the 'dead/old' electrolytic caps, Without heating, Grip the body of
the cap with pliers, or fingers, and bend the entire body of the cap
over to the PC board. In the Electrolytic caps, like the ones on the
A9 board, the internal connection to the leads is made just inside
the body of the cap and break off clean.... allowing you to pull the
entire capacitor body off of the remaining two mounting leads left
behind, still in the PC board. These single solid wire stubs are
completely easy to heat, and quicly remove, from the pc board without
damaging the PC board from excess heating. Don't worry if the solder
hole is clear of left over solder, that gets taken care of in the next TIP.
Tip(2) After TIP(1), Heat one side of each PC board hole, with a
pointed soldering iron tip that is centered on the hole. When the
solder is melted, use a round (not flat) wooden toothpick, to push
through all the melted solder from the opposite side of the hole. The
solder does not stick to the wooden toothpick, and the toothpick
tapered body displaces all the excess solder from inside the PC board
hole. So, the PC hole is left open and solder free, and ready for new
components to be inserted.
73,
Ben - WB2RHM
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