>Is it possible for an EPROM (16C63) to check out as blank, program, and
>verify correctly but not be fully erased?
>
>I am working with the 16C63JW.  I have 6 that I rotate through my eraser as
>I am programming,  occasionally it seems like things just go screwy.  Am I
>not leaving them in the eraser long enough?  Please let me know your
>thoughts on this.


I think so Steve.  I've had the same problem with the little '54s.  For some
reason 15 minutes under a 4w lamp will generally give me a chip that tests
as "blank" but screws up when programming it.  Using 30 minutes I don't
recall running into the same problem until the PIC gets quite old (lotsa
programming/erase cycles -- I don't know the exact number but it's over 75).

Cheers,

Win Wiencke
Image Logic Corporation
ImageLogic@ibm.net