On Thu, 2007-05-17 at 21:56 +0100, peter green wrote: > > Or at least find out why this doesn't work. Anyone know? > my first thought would be that the ground of the low voltage supply is somehow (possiblly via a peice of test or programming equipment) connected to mains ground. That would also be my guess. If you've got say the ICD2 connected to your PIC, and that's connected to your PC, which connects it's local ground to earth ground, magic smoke is the result. If you are using a laptop perhaps the power adapter for the laptop grounds the negative rail? TTYL -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist