======== Original Message ========
We have experienced an intermittent missing hole (not drilled) defect on
one part number.  On each of 20 panels I have analyzed, the same hole is
missing.
The entire drill file is intact on the mainframe, however, some kind of
glitch must be occurring either during downloading the data across the
DNC or executing the program on the drill machine.
We use Hitachi drill machines.
Has anyone run across such a problem, or does anyone have an idea what
might be the cause of this mystery?

drilbert
======== Fwd by: Richard MacCu ========
Another thing to try, is to test the memory on the drill machine.  If you
have a RAM chip that is bad there may be no indication.  I've had the same
thing on Excellon and after the factory sent a memory test program we found
a bad card in the controller.