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Small IR gooseneck spot heater?

flippineck

Sep 8, 2013
344
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Sep 8, 2013
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344
Wanting to desolder WSON8 6x5mm chips without damage so they can be read with a programmer off the PCB.

I can get them off ok using a hot air station and tweezers but it requires a fair time of heating at around 340'C.

They have a big ground pad in the middle of the chip, sandwiched between chip & PCB, can't get even the finest soldering iron to it nor will chip quik 'wick' under enough to help.

Hot plate on the other side of the PCB might help but, want to avoid heating large uninvolved areas unnecessarily.

Thought of taping or clipping a small self-temperature-regulating / 260'C peltier heater to the other side of the PCB but, there's a few SMT transistors / resistors etc spotted about & in the way.

So I got to thinking, does there exist anywhere, a tiny IR filament spot bulb that could be suitably shrouded and fitted on the end of a gooseneck, such that one could have it as part of the desoldering table/fixture and aim it at the precise spot on the back of the PCB whilst hot air desoldering from the other side?

Maybe incorporate a thermocouple to get some idea of temperature?
 

Martaine2005

May 12, 2015
4,351
Joined
May 12, 2015
Messages
4,351
You’ll probably find that that heat dissipated in the rest of the ground plane. Which is why the heat plate warms it all over. Besides that, surface tension might actually damage other solder joints due to expansion in one small area. I could be wrong though.
I’d be more inclined to whack up the hot air to max and try to remove the component quickly but still circle to pre-heat the surrounding area as normal. Again, I could be wrong though.

Martin
 
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