Got a pic 16f628 in a circuit here, 7805 volatge regulator suddenly died, thought it was due to overvolage from the supply (sometimes did go outside 7805 specs), so put a resister in series with the input of 7805 (and replaced the burnt out part), this brought the input volatage down to about 12v, checked the output volatge was still 5v, it was, checked an led twisted onto a resister in the ic socket, yes it worked.
Put the micro back, not working, 0.9v supply, 1.9 into volatge reg, hmm, moved down resister values, until I ended up with 11 at the volt reg input, but only 4.5 at the output, hmm, the volatage reg didn't blow straight away before so, I'll take the resister out, and just check quickly, <BANG>, smoke pours out the micro, then stops - voltage reg died again, I pulled the micro out again, and thought after all the smoke that came from it, I've got nothing to loose checking resistance across the power pins, - about 8 ohms, anyone know what would cause it to short out like this?
Put the micro back, not working, 0.9v supply, 1.9 into volatge reg, hmm, moved down resister values, until I ended up with 11 at the volt reg input, but only 4.5 at the output, hmm, the volatage reg didn't blow straight away before so, I'll take the resister out, and just check quickly, <BANG>, smoke pours out the micro, then stops - voltage reg died again, I pulled the micro out again, and thought after all the smoke that came from it, I've got nothing to loose checking resistance across the power pins, - about 8 ohms, anyone know what would cause it to short out like this?
