Perhaps....I might have one floating, but I believe it has a voltage divider on it as well. I don't have the schematic in front of me. Now, if I setup to make that pin an output...should eliminate that from being an issue. Now, one thing I did late last night (after taking care of the other days fires) was set up both boards, ran them both independently and looked at the register data from the A/D. Again, good board good...bad board...bad. So I took power from the good board and jumpered over to the bad board and it APPEARS with at least with the voltage divider input, it was no longer getting wierd 7F data but the sensor still was not reading (yes, same exact firmware load). Thus the problem...gotta be power! No wait....thats why you don't do stuff at midnight when you have been up since 4am. The voltage input that was being measured was the INPUT to the DC/DC so by jumpering over power, I eliminated the source. Makes sense that the reading was not consistant, musta been leakage I was measuring. But of course, didnt think about that till this morning...... "Alan B. Pearce" wrote: >I'm not discounting firmware yet, other than I have >two boards that have NO issues at all, while two others >do. And I can take a chip from one board, drop into >the other and it works just fine. Thats why I am looking >for some sort of external stimuli that would be present >on the bad boards and not the good, but the question >is....what to look for that might cause such a condition. ISTR that this is the sort of funny thing that can happen when ANY pin that has an A/D input on it goes outside the VCC/GND limits. i.e. is any of the other A/D inputs floating/tied to some strange voltage on the other boards? -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist --------------------------------- Yahoo! Music Unlimited - Access over 1 million songs. Try it free. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist