I have a circuit that uses a 16F877 and I was having trouble getting my chip to send data out serially on a couple pins. It would work on c.6, but when I tried B0 or B2 it basically did nothing. While trying to figure out what was going on I connected my Oscilloscope. As soon as I connected the ground line the circuit started sending data out as I intended. the probe end wasn't touching any part of the circuit, just floating in air. When I disconnect the ground, the circuit again doesn't work right. I have tried adding a couple different size caps, with some varied success, but nothing definitive. My circuit is powered by a 9 volt brick, so there isn't a true ground on the circuit, but I've never noticed problems before with that setup. Anyone have any ideas?