Before touching anything, this was the state of the first loop power stabilisation with the loop disabled.
 - 0.708 W diffracted
 - AOM modulation input 0.353 V
 - REFSIGNAL on -2.00
 - AOM monitor voltage (on MEDM screen) 0.417 V
 - offset slider 8.00
 - the Transfer 1A and Transfer 1B signals displayed on the MEDM screen were fluctuating wildly
 - the pre-modecleaner transmission seemed quite stable

    The input beam alignment to the AOM looked acceptable compared to the input aperture.  The angle
of incidence of the AOM with respect to the input beam was okay.

    With the offset slider on 0, 0.289 W was diffracted.  On 8, 2.986 W was diffracted.  In both cases
the REFSIGNAL slider was moved all the way to -10.00 to take it out of the equation.  With the REFSIGNAL
slider at -2.00 (the setting it has been in for a while), something like 6.8 W was diffracted.

    My guess is that with the servo settings as they were, the BUF634 high speed buffer that drives the
AOM RF driver was in a state where the in-built thermal protection kicked on and off.  I have no hard
evidence to prove this, other than the observation that as the offset slider voltage increases, the
diffracted power is a little less stable at the milliwatt level (based on a 10 second average) and
the AOM modulation voltage starts varying by 2 mV.

    The offset slider was lowered to 5.60.  The percentage diffracted power needs to be re-calibrated.

    A couple of other observations in passing.  With the AOM monitor reading 0.385 V, a multimeter measuring
the applied AOM modulation voltage read 0.324 V with the offset slider at 5.60.  When the AOM driver was
disconnected, the multimeter read 0.488 V.  There appears to be an offset between the displayed AOM modulation
voltage and the measured one of ~20 mV.