RE: Spektrum DX-7 Problem ??
Some more test seems to have isolated the problem to the one servo and /or its extensions. Changing ports on the rx (rt ail, elev or rudder) still gives an occasional erratic motion on that servo, but no others. That would seem to point fairly conclusively to the servo.
I have noticed the glitches are more frequent when the battery voltage is high, say over 6.5v open circuit. When the OC voltage is down around 5.7v, the glitches are almost non-existatnt. Don't know if this is significant. I don't believe the problem is with the servo extensions; I have pulled, pushed, twisted, squeezed, even cussed at, every connection and cannot induce the problem - it just occurs randomly, sometimes when you're moving the sticks and sometimes when the transmitter is just sitting there on the bench.
One other thing bothers me - I cannot reproduce the problem when that servo is plugged into another plane with a JR955 RX or an R2000 RX; I've tried both. Even with battery voltage at 6.95v. That's not to say it won't do it, but I've watched it for several 20-30 minute periods and never observed an uncommanded movement. Maybe just coincidence, but I don't believe in coincidences. Does the JR RX's provide some sort of voltage regulation or filtering?
Anyway, that's what I've found to date. Frustrating.
Jack