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Jon Elson

wrote:

The latest motherboard I did was an IBM that had a solid plane (no thermal
reliefs) on the top AND bottom of the board. My Metcal had enough heat but
the little wire through the board couldn't conduct the heat fast enough. I
ended up with the soldering iron in one hand and a hot air gun in the
other. The holes ended up very clean and it runs like new again.
Yes, this is a problem. I used a Weller WMP which is a 65 W mini-pencil
iron, and with the most massive tip available for it. First,
dilute the no-lead solder with SnPb solder to lower the melting
point of the solder. Then I heated each
capacitor lead for 10 seconds or so and then levered the cap which
pulled the pin back through the board a bit. Then go to the other pin
and do the same. After one cycle of that, the cap is far enough off the
board you can pull one lead fully out of the board, then the other.
Then, I used the 65 W iron on one side and a Pace desildering tool
on the other side at the same time, and it pulled the solder out of
the hole. Resoldering the new caps was a breeze compared to the
extraction part.

Jon