Don't the CSM gyros also require a specific start up method? Like having it in heading hold as you turn on the heli, and keeping the heli still, (straight) as the gyro sets itself.

I haven't flown a CSM for a while but remember that you have to use some caution with the start up procedure as with the newer futaba and jr hh gyros.

That would give you the exact heli response as what you are saying. heli rotates slowly to one direction..(due to gyro not centered) then with 1 click trim input, (you now are telling the gyro to go the other direction all the time (not ITS netural position)) That would cause it to slowly, and continually turn the other direction.

Might be a simple solution, but I'll bet you a buck!

Jeff