Servo problem...

[petokang]

Hi, I was working on my losi mrc pro rig.

After all ther wiring was done, I turned on the switch of my ESC and transmitter, my Hitec HS-645 MG servo started to turn to one side and keep trying to turn even though it reached to the end.

I tried to control it with my transmitter but didn't do anything.

So I tried my old HS-303 servo and it worked just fine.

I'm using very old Hitec transmitter and receiver. Could that be the problem?

Or is it just my 645 MG is bad and have to replace it?

I'm not very good with electronics on RC...so please help!

Thanks.

[Trubble]

If a different servo worked fine, I'd be less likely to suspect your radio gear, that stuff's probably okay. I'll assume since you tried another servo, your trims and EPA's aren't too wacked out, either. Sometimes digital servos don't care to work too well with AM/FM radios, but I can't find anything that tells me if your 645 is a digital or not. (Nope, ServoCity lists it as an analog, that shouldn't be the problem)

Sounds like the pot (potentiometer) inside your servo has either given up the ghost, or has become disconnected somehow. Been a long, long, long time since I've seen the inside of a servo, someone else will have to chime in here with some troubleshooting tips.

Lately have you.......

Taken apart the servo?
Run without a servo-saver?
Cranked the wheel while the steering was bound in a tight spot? (to the point of hearing snapping and cracking)
Rolled your crawler?

Could be that somewhere in your geartrain you just skipped a few teeth or had some other gear mis-alignment/ failure issue.
Difficult to tell from the outside, at this point.