what makes a servo gives up under load?
 

The servo looked like it was working ok but when I put a load on the control surface the servo would give up and not hold. At times I could move the control surface up and down with no resistance, like it was not even plugged in. Some times doing that I could feel the servo push back a little. I know when the signal wire is not connected the pos. and neg. connections don't do anything to hold the servo position. At any rate it is getting yanked and a new one installed, just trying to find an answer.

Clean the electrical (plugs) connections. Could be that the voltage to the servo is not what it should be.
Try that first.

How powerful a servo?

the servo was a Futaba 3010 on a 2100 LiFe pack, about 90 in. oz.

Bypass the on/off switch and plug your battery directly in to the receiver. Is it still weak? Put a known "good" servo in its place. Dan.

By the way, that is not a high voltage servo. What is your battery pack's voltage? Dan.

Here's a good voltmeter you can use to make sure you are not getting a voltage drop in any of your lines.

http://www.horizonhobby.com/digital-...ltmeter-han171

Sounds like stripped gear train to me. Easy to check just remove the pushrod and with the power off just cycle the servo with your hand stop to stop and any stripped teeth will become obvious.

John

The voltage on the battery is 6.6 v. The gear train is not stripped. At times I could move the control surface up and down and run the gear train backwards like the servo wasn't plugged into a receiver. The servo did the same thing plugged directly into another receiver with a battery plugged directly to the receiver. I am guessing it is some sort of electronic problem in the servo. Just wondering what sort and why it happened.

I would have to ask if there is any wire that has been crushed, crimped or repaired? I have a friend who kept fighting radio problems and it was damaged servo extensions. He would pull the servo but not the extension. Servo not getting the amps all the time. I would plug it in to another receiver and see if it acts the same. If not, ditch it.