This is a very big moment.
Remember when power (specifically 115vac 400hz) is first supplied to the unit (before switching the MSU on) there'll be a high pitched whining noise from the back of the INU. This is good.
Regarding the video, it's only important to capture what the gimbal does at turn on (video to show the CDU display + Gimbal movement + your hand switching MSU to stby - if possible). We can gain a lot of knowledge from what the gimbal does at switch on.
If it does turn on without smoke - remember to write down the bias figures (as a priority) - as previously mentioned in the thread.
This is what I expect at first turn on.
60% chance that nothing happens - other than smoke from the power supply (not good)
30% chance the gimbal cages (or tries to) and then maybe spins wildly after cage mode is complete - possibly due to failed gyros/accels/servo bd. (possibly be able to fix)
5% chance that system tries to align but then fails due to the calibration being way off (High possibility to fix with some calibration) Action/Malfunction code will be displayed and a flashing 'Warn" on the CDU.
5% chance of successful alignment - nothing to worry about.
Good luck. :-)