Hi Steve,

My ICSP connector is wired as follows:

1-5vdc from EPIC
2-no connection
3-no connection
4-no connection
5-ground
6-ground
7-RB6
8-RB7
9-no connection
10-Vpp

I have a blocking diode between the MCLR pull up 1K resistor to prevent the programming voltage from damaging my circuit. I have another board that has ICSP on it and there I have a VFDisplay data lines on RB6 and RB7 so I put a DPDT toggle switch between the display and the ICSP connector so I don't cause any problems with the display while programming. It works okay also.

I did notice on your schematic that it shows a 16F628 and your posts mention a 16F628A. I'm assuming that this was the only label of the chip diagram being different.

Perhaps this could be of help: (From MELabs help support)

Note for PIC16F62x: RB4 should be connected to ground to prevent interference from the Low Voltage Programming pin.

If you can program through the ZIF but not the ICSP connection them maybe there is something wrong between the ICSP and the PIC.

At this point I'm out of ideas. I know I've had my share of head scratchers lately too!

BobK.