Up until now I have programmed 100's of PIC16C52's, but last week I programmed a batch of 25, all programmed and verfied OK. I did my usaul radom test and found some which didn't work, I test all of the devices and found about 40% did not work. I reprogrammed the fuses and most then worked. I was left with 6 which just would not work but they verrified OK. I sent out 25 fully tested devices to my customer and have just heard from him that all 25 devices do not work. Has anyone come across this before, the devices were all date coded 9711SCN. Any ideas. Ken. +-----------------------------+--------------------------------------+ | Ken Hewitt G8PWC | Email ken@welwyn.demon.co.uk | | /\/\/\/\/\/\/\/\/ | Homepage www.welwyn.demon.co.uk | +-----------------------------+--------------------------------------+