HOORAY !!!!!

I have programmed all my 18F2431s and 18F4431s

Here is my response to Microchip support.

Thanks for the suggestions.

I had already tried connecting AVdd to Vdd and AVss to Vss as I noticed that they had slightly different voltages on them (5.01 and 4.97) but that didnt make any difference.

I attempted the "manual" method you suggested but didnt have the option of "Erase all before program" (MPLAB 7.30)

I then upgraded to MPLAB 7.42 and still didnt have any luck with the 2431 so I went to the 4431. Again these failed to program. A blank check revealed that they werent blank and attempts to erase the devices failed. I removed the 2.2uF capacitor and successfully erased it. I then discovered that I could now program these WITHOUT needing the capacitor.

I returned to the 2431 WITHOUT a capacitor but WITH a 1K resistor between pins 7 and 11 as that had been succesful for others on the PBP forum, SUCCESS

It would appear that the root of my problem was MPLAB 7.30 as I couldnt program 4431s either. I do need the AVdd connection to program 2431s but since upgrading to MPLAB7.42 the problem seems to be sorted.

Regards

Keith

Note to Steve: I too would appreciate a tutorial on ICSP with Picstart as it is something I have never tried. Having said that, all the PICs I use now have bootloaders but I think it would be a useful to know.