I can see the head of the bolts holding the toroids in place, so will assume that the toroids bolts go into some form of
rivnut. You need to use a
thread locker such as
Loctite 243 to prevent the bolts coming loose again. There is a continual vibration with toroids which have a heavy dimmed load passing through them and this can lead to the bolts working loose. This is why touring racks usually have their chokes potted, to overcome any vobration and also stop any audible noise from the windings. You can get your repairman to sleeve the bolts as well.
It is a pity your video did not show the
fader being moved so we could see if there is a correlation between the
fader movement and the lights flickering. It could be dirty faders causing the flickering. If your
desk is a two
preset desk do you get the same flicker using either top or bottom
fader.
To clean the faders using a contact cleaner such as CO Contact Cleaner, definitely not any automotive dewetting spray such as WD40, turn your lighting
system off, unplug your
desk and if you are competent enough, remove the top or bottom
cover so you can see the backs of the faders. Place a cloth along the lower side of the faders to soak up the contact cleaner that will come out of the faders. Turn the
desk on its top
edge so the residual flows to the top of the
fader and flush a generous amount of contact cleaner into every
fader, moving the
fader knob a few times then leave the
fader at the top of its travel, in this case it will be at zero as the
desk is upside down, while the contact cleaner dries.
I do this cleaning upside down as the faders spend most of their time at zero so I want to
wash the residual dust
etc out the top end to avoid any buildup at the bottom end.
This generous flushing will only work once or twice, then you will need to have any faulty faders replaced.
Of course keeping the
desk covered when not in use will usually avoid this problem happening. Most reputable manufacturers use faders with a dust
cover or self closing rubber strip to try and help keep their faders clean. But don't let that stop you developing good habits such as covering a
desk when it is switched off and not in use.
let us know how you are getting on.