Padu wrote: > From: "Spehro Pefhany" > >>If you're looking at it on a 20MHz or better oscilloscope and the signal >>is going cleanly from 0V to ~1V with nothing connected to it, then you've >>hosed the output. >> >>If you're reading the average voltage on a DVM, it could be just about >>anything. If you don't have any better tools and the chip is soldered in, >>reprogram it to set the port high and read the voltages. If you've got a >>socket, swap chips with a known-good chip. >> > Sorry, I should've said. I'm looking at it with a 100MHz oscope, and the > chip (PLCC package) is soldered to the board. I don't have a desoldering > tool for this type of chip, so removing it from the board I believe will be > very difficult. Not really. Get a paint stripper hot air gun. Make a air directing funnel out of aluminum foil, or plumbing parts, to get a smaller diameter hot air blast. Carefully bring the running stripper up to the chip on the board (board held up side down). The solder will melt on all pins very quickly and the chip will drop off the board. (you may need to tap it). Be VERY careful to come in quickly and pull away quickly so as to not overheat the other parts and traces. Should take all of 5 seconds with a preheated stripper. > I have lots of spare ports, maybe I could cut the trace that > is connected to the damaged port and re-wire it to another pin using hookup > wire? Cutting the trace would also let you confirm that it is the PIC that is fried, and not the logic gate that it connects to. If the logic is fried, it could be clamping the PIC pin to 1V (about a diode drop at 20mA) Robert -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist