RE: Odd Servo Problem
Short story made long: Many, many years ago, when I was a young teenager, I horded all the R/C magazines I could get my hands on. Even when we had a youth event for the young people of my club, they were giving away tons of free R/C stuff. Well, I snatched up all the magazines, instead of the odds and ends of plane parts.
Well, literally just 2 nights ago, I was repairing a Gentle Lady glider that I'd let lie dormant for years. I had a similar problem: when I plugged the servo into the receiver of my (VERY OLD Futaba AM Attack4) it seemed that only the elevator channel was working, and maybe one other channel. I figured that since I'd let the radio sit for so many years, that it was likely just expired now, and that was it. I was even sitting there for few minutes contemplating dissecting it. (I really enjoy seeing the innards of dead electronics). Instead, I took the radio out, unplugged the receiver, got up to walk over and throw the whole thing in the garbage when it struck me....
One of these magazines that I'd read oh-so-many years ago (actually it was likely in more than one of them) had mentioned that sometimes the servo reversing switches got gummed up, or corroded, and would cause havoc on the operation of the servos. The solution was to simply slide the servo reversing switches back and forth several times, and voila! your servos would be fine again. So, highly doubting that would help in this case, I plugged the radio back in, and tried it...
I now have a radio that is working superbly, as it always had! All four channels working flawlessly!
So if you have MECHANICAL servo reversing switches, toggle them a few times and see what happens!
Let us know what works for you!