Is anybody using the JDM serial pic programmer?
I built the Pic-Programmer 2 version and I'm debugging
it before pluging in a live pic. (www.jdm.homepage.dk/newpics.htm)

It seems that the VPP (MCLR) pin goes from -.6v to +12.87 volts.
I'm worried that the negative voltage (when it should be zero) might
damage the device being programmed. I tried adding a 1n4148 clamp
diode from MCLR to VSS (Anode to VSS) and that brings the 'zero'
voltage down to -.37v or so.

VDD runs +5.11v (exactly what the Zener diode is rated at). The
+12.87v for vpp is about what it should be given the 8.2v and
5.1v zeners plus the drop through Q1 (and that 8.2v zener might
be the low side, I didn't measure the drop across it).

If the slightly negative voltage on MCLR isn't fatal, I guess
the programmer is good to go. Any ideas?