I have been experiencing an error signal which  I am unfamiliar with on
our VG Prism Series II mass spec. If anyone has any information they can
share or suggestions on how to trouble shoot this problem I would
greatly appreciate it.

We get a "FAULT electron volt PCB" error signal  when we boot up our
instrument with HT (high voltage) turned on.  If we boot up with HT off
we do not get the error signal, instead we get a source filament in
limit error signal which disappears after a few seconds.  With the
"FAULT electron volt PCB" error we have no beam. When we boot up with HT

off, then turn on HT, we do have a beam.  After a few minutes to several
hours the
"Fault electron volt PCB" error returns and we lose the beam again.

Thanks in advance for your thoughts,
Margaret