8048 board, probs programming 12f675

I carefully built the 8048 board and was pleased to have your example code running on the 16f627 immediately after construction.

The problem is I cannot program a 12f675, I get a ‘No devide ID received’ message. I’ve circuit tested the socket and checked the soldering, everything seems fine.

The wierd thing is when I first built the board, I did manage to program a 12f675 once with some test code, but the PIC worked sporadically, I tried to re-flash it and got ‘No device ID received’.

Stranger still is that with the 12f675 on the board and SW5 set to PROG, LD1 flashes (what the test code was supposed to do)!

My question is, could this be a problem with the flash software or could I have damaged the PIC during a flash? Is there an easy way to diagnose this?

Any help is greatly appreciated!
Alex

If you can program a F627 the hardware should be OK.
But, please check if VPP is arround 12,5V, if not check if R14 is 1K (not 3K3), maybe the VPP is too low?

Thanks for the quick reply. I don’t have a 15v power supply to hand, but when I buy/build one I’ll let you know if this works.

I’m worried I may have damaged my pics, is there a simple circuit I could build to test this?