CS SS Transmitter
 

I recently purchased this seven channel FM SS transmitter to match my thirty year old Aquila Grande glider which I am refurbishing. I no this is an antique but so is the glider and I'm just retracing my past modeling experience. This is my question. The transmitter has a problem of servo interaction when full up elevator is commanded. This problem does not occure when full down elevatori is applied. I reversed the direction of the elevator servo and now the servos interact when full down elevator is ininitated but does not occur when full up elevator is applied. Can someone tell me what is going on. The person I purchased this used transmitter from said it worked 100% for him. Since I purchased this item through EBay I have initiated a claim for his description as deceptive and missleading. He never advertised it as is condition. Is this problem something Airtronics will still work on or is it DOA?