I have exactly the same situation was.
Besides, I have also the monitor was beeping in high tones, the problem was
Many have said I need to replace it — that is desoldering and put the new one, but I was afraid.
I also read that the throttle can be "calm" Bay it with epoxy — I also did not do.
Made "on the knee" — took the screw, the sharp end blunted on a rock and twisted into the body of the monitor exactly hitting the ground off end into the throttle and not a lot of twisting with a screwdriver pressed harder the throttle to the Board and everything started to work fine. It's perverse — but I didn't want to carry the monitor in service, there was neither the time nor the guarantee.
Before all this hit to do with your finger (in glove) on the throttle — if it helps — it's all right and you can "press screw", if not then consult with any Radioelektronika.