>From what I remember, the forward scatter signa goes through a pre-amp
on one card, then into a peak sample-and-hold, then is multiplexed onto
the X-ADC. The threshold trigger comes off the analogue ssignal after
the pre-amp. If you are triggering on scatter OK, as you seem to be, and
you are getting the X-ADC to work on other parameters, I would guess that
you have a problem in the samnple-and-hold or the multiplexer, or the
control line to the multiplexer. If you still have your schematics, and
that wonderful extender board, then the problem should be easy to find
for any competent electronics engineer who happens to be hanging round
your lab.
Good luck in finding it.
Bruce Milthorpe