Yeah - the 3421's seem to be fine "on their own" with a 5 cell pack - it's when they are used with a gyro and a 5 cell pack, that the 3421's had a problem. Maybe the gyro just causes them to move much more frequently than Joe User does when he wiggles the sticks, such that the "active cycle" is too high to allow the components to remain cool ? I know that I lost two sets of 3421's that way, David Reid and one of his buddies also lost two servos apiece, and Harley Condra's 3421's melted their way out of their cases if I remember correctly. After losing my second set I installed a voltage regulator, and that seemed to fix the problem : whereas I had to replace the 3421's TWICE in the first 50 or so flights in the unregulated setup, the next 2 3421's in the regulated setup have well over 250 flights on them, with zero problems.

Gordon