test sequence in this video: open aperture, then f/9.5 (when motor of diaphragm is not used) and bulb.

as you can see on the bulb the motor driver is actively heating up. but not critical.

please note that this camera uses 3 identical motor drivers. exactly the same as leica minilux, ricoh gr1, gr21, nikon 28ti/35ti, fuji ga645zi and i think in some cameras else. these drivers are very reliable and only once i got a camera with a faulty motor driver after another repair. then the driver was damaged by overheating during dismantling in sendean cameras uk.
here is this post https://awayrepairs.livejournal.com/1...

in general, i think this is very cool and i really like the camera for this (and many other reasons).
three drivers are needed because the camera actually has 3 motors.
two drivers are needed for two motors that control 2 shutter curtains (gelatin) each, due to which a shorter shutter speed is provided.

and the third motor have classic type of stepper motor with two coils who control the aperture and fix the shutter of the second curtain in the open position with hook.

because shutter motors are rather solenoids than motors. they can only move forward and backward and, but not in a circle and they have only one coil and magnet inside coil. the same motor is used in the minolta tc-1. and as far as i remember, a very similar shutter is used in lenses of medium format cameras rollei 6000 series.

post about this repair you can read on my lj page:
https://awayrepairs.livejournal.com/2...
my instagram for repairs @awayrepairs