Malfunctioning VT240 - help please

[Jon Elson]

> I confirmed the bad one by removing the piggyback and the 
> failure returned. Now I need to desolder the bad one 
> without ruining the board. I may just cut the leads off 
> close to the bad chip, and solder the replacement to the 
> stumps. (Normally I remove the legs and install a 
> machine-pin DIP socket). Or just solder the piggyback and 
> leave it there... thoughts?
>
Cut the leads close to the body.  Apply a soldering iron to 
each lead, and pull the lead out with tweezers,
simultaneously heating and pulling.  This is very gentle to 
the board, just doing one at a time.  Then, you can vacuum 
out the holes and install a new chip or socket.

I've done this many times, and never wrecked a board.

Jon