Allentown, PA
Quoted from Elicash:Hello all, so somehow I fried ULN2803 on the MPU.
My question - what is best / safest way to do this? Is it better to cut the little legs on the ic chips then desolder? Or should i desolder each hole and try to push the little legs out after all solder has been removed? Anything else to consider on this particular issue?
Here's my method. Cut off the chip but leave as much lead as possible. Then reflow the solder for each lead adding a little fresh solder. Using tweezers grap the extra chip lead and reflow/melt the solder again. Using slight pressure pull out the old lead while the solder is melted. Because the solder was already reflowed once this process should be pretty quick reducing the heat exposure to the PCB. Now you can desolder the individual holes. Personally, I desolder the holes with Hakko desolder gun.
And yes socket the 2803. This chip is a know failure point for WPC MPU. On later versions (WPC95) the chip came socket-ed from the factory.
Other notes: (1) use good solder. Good solder doesn't require flux. (2) if you have a good solder iron the heat range is 650 to 700. (3) Be carefull using a vacuum pencil to desolder - I find the have more vacuum then my gun and lift traces. Personally, I would use a good solder wick over a vacuum pencil.
Good luck.
