Thanks Ben, I added the tips to
http://tentecwiki.org/doku.php?id=565pwrdistfail
73, Barry N1EU
On Thu, Mar 26, 2015 at 9:34 AM, Ben Antanaitis - WB2RHM <wb2rhm@wb2rhm.com>
wrote:
> 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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