i wanted to ask around how you go about unsoldering ICs which might be good and required in the future.
do you use freeze to cool the component down before starting? or is this more likely to screw up the ic through stress?
thanks, Konrad
Apply fresh solder to all the pins and use a good temp controlled iron and a solder puller. Apply heat for about 2 seconds per pin. On occasion you may get a tough pin so reapply fresh solder. If you are inexperienced you may want to let the chip cool after pulling half of the pins. If you are removing a lot of ic's this would be a good practice anyway. I used to service commodore 64's and they would always blow 8 rams at once.They used .028 holes which made removal withiut pulling traces a pain. When you get good you can pull 2 or 3 pins at once. Also, you may want to use a small flat jewlers screwdriver to push the pins inward (from the componant side of the PWB) to release them after sucking. You can also (if there is room) twist the chip a fiew deg with pliers to release. This works great upto about 20 pin dips.
No, that'd be going from one temperature extreme to another.
If you you're harvesting a junk board for parts, heat it up with a heat gun until the solder melts then tap it with something to make the parts fall out.
I would expect freezing first to juat make things worse via greater thermal shock. I've never done it, though.
------------------------------------------------ Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA
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