OldSynths

>> Can someone advise the best way to desolder chips from a circuit board?
>> I am working on my CS-60 and want to replace 40xx chips with new, but
>> dont want to do more damage than good.
>> I will be putting in sockets in their place to make repair easier in
>> the future.
>>
>> Is there a good method or desolder tool that heats the whole chip at
>> once?

An expensive desoldering station probably works like a charm. I've never
had the pleasure of using one.

>> The only other way I know is to clip off the leads, remove the chip,
>> and then desolder the remaining pieces of lead from the board.

This is the slowest but safest way, especially if you're not worried about
saving the chip.

>Many swear by solder wicks...but I've never gotten the technique.  A heat
>gun with proper tip is usually the best I think.  Solder suckers (the $6.00
>type with a pump and trigger) are ok often though on double sided can be
>quite a challenge at times.  Heat gun in those cases I believe is the only
>good way not to damage board. -Bob

Since this is a vintage piece of gear I'd forget the solder wick (it might
be useful for cleanup if used sparingly). I only keep some around for those
occasions when nothing else works and I know the board can take the heat.
I've heard people who know what they're talking about praise the heat gun
approach but I've never tried it myself. In the past (mid-eighties) I
repaired a lot of commercial equipment that had been in the field a long
time and we NEVER used solder wick because the danger to the board was too
great and a quality, properly-maintained solder sucker worked far better
and faster (we used Soldapults that cost $20-30 apiece back then). Today a
desoldering station would probably be the commercial approach to this.
Interestingly the tech students from the local community college had never
SEEN a solder sucker--that was the beginning of their real education in
circuit board work.

We also defluxed the boards with copious amounts of CFC's. Those were the
days...

-- 

Terry Bowman, KA4HJH
"The Mac Doctor"