Do you have access to an RF power meter capable of working at VHF and a 50-100 watt dummy load at 50 Ohms? An RF spectrum analyzer and sampler might help too.
Else send the driver to Gooch in England.
The modulator is subtractive, as you have guessed. So it will lase CW unless the AOM crystal is good and the RF driver works / is triggered.
That driver has a first pulse suppression system, so the designers were worried about "Giant Pulsing" damaging cavity optics or the laser crystal if the Q-switch stuttered.
Steve
Qui habet Christos, habet Vitam!
I should have rented the space under my name for advertising.
When I still could have...