On 5/18/07, Brent Brown <brent.brown@clear.net.nz> wrote:
> > > If you are using a laptop perhaps the power adapter for the laptop
> > > grounds the negative rail?
> >
> > Actually I've disconnected everything now, I'm testing with just the
> > parts in the circuit I attached and it doesn't work. (I already burned
> > the computers COM port, luckily I also have a usb-rs232 adapter).
>
> Oscilloscope ground clip providing the short to ground?
>

Bingo!! I wasn't even using the scope but surely the probe was still
grounded to the circuit. Thanks, I'll sleep easier tonight :)
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist