Tam, One point I'm not clear on. Are you using the programmer simply as a PIC programmer (putting the PIC into the ITU ZIF socket)? Or are you hooking the ITU board up to your circuit and attempting to use it as an "in-service programmer"? If the latter, do you still have a problem if you remove the PIC from your circuit and plug it into the ITU programmer ZIF socket? Frank McKenney / OS/2 Advisor (OS2BBS) McKenney Associates / Richmond, Virginia / (804) 320-4887 Internet: rrs0059@ibm.net / TalkLink: WZ01123