I have an old 8UAP and have had two occassions when elevators on two different p[lanes went hard up causing the planes to crash. I have replaced the radio but would like to know where the most likely problem lays. Would it be in the basic radio [box] or in the transmitter module?

Thanks,

Gary

There is no way for us to determine where a difficulty may be.  It could be in the transmitter, it could be in the servos.  It could be caused by outside interference and not be the system at all.

We'd not be able to make any determination unless the unit was here and the difficulty happened while we were working with the system.