This morning I installed the modified pre-modecleaner servo.  In short, I could not lock the pre-modecleaner with it.

    The difference between the modified board and the in-service one, is the addition of two active notches to notch
out the pre-modecleaner PZT resonances.  The phase delay switches were changed to DDDDDDUUU to restore the sign of the
error signal.  Despite what I think is the correct feedback sign, I could not get the pre-modecleaner to lock.  The
(original) in-service pre-modecleaner was re-installed, along with restoration of the phase delay switch settings in
order not to delay commissioning work for this morning.

    Back to the EE Lab with this one.