Hi All,

I have an odd one here. On a PCB I made myself, I had a little project working. It's a nixie clock, with '595 shift registers. Everything was working fine, then the nixies stopped working correctly and the PIC16F88 wouldn't program. I am using ICP.

Buncha troubleshooting later, I discover this odd fact: With 5V on the MCLR pin, the sucker won't drive the nixie correctly. With 2.5V on the MCLR pin, it will. It has the standard pullup on MCLR, 10K and if I put a 10k pulldown (making a voltage divider) resulting in 2.5V being on MCLR it works.

What the heck?

Jonathan