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Servo swinging on startup

2K views 6 replies 3 participants last post by  Toeknee 
#1 ·
Hi all, I have a strange problem with an HSP 1/10 Nitro Monster Truck. I got the truck second hand and have replaced a number of missing/broken parts and have no idea of any issues that were there before I bought it.

I have a number of buggies and have not had this issue before.

When I turn the power on to the Rx, the throttle servo swings clockwise (throttle on) about 90 degrees and then returns to neutral after which it operates normally. The travel is so far that it is eventually pulling the linkage cap right off the carby after a number of restarts, despite being a standard HSP E6000 servo which is only 6kg.

I turn the Tx on first, then the Rx, but the same thing happens either way.

If I swap the steering to Ch2 on the receiver, then the same behaviour happens with the steering, full left lock then back to centre, afterwards operates normally. So is a Ch2 on the Rx issue, not the servo.

I have done 'bind' a number of times and the same thing. It is not the bind.

Ok, so then I swapped the Tx & Rx for a different set. With a completely different Transmitter and Receiver in the truck, it still does the same thing??? So is not the receiver or transmitter.

I am at a loss, so am hoping someone out there can help, any suggestions appreciated.
 
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#2 ·
That's very odd. So different receiver and transmitter and you get the same issues? It's possible one of the servos are bad. Unplug one servo. Plug the other into the offending channel and test. Try the same servo on the other ch. Try the other servo on both channels.

Sent from my SM-G930F using Tapatalk
 
#4 ·
Thanks for the replies.

GTO Joe - Have done that test. When I plug into the other channel, the first servo works correctly and the other plays up? It is Channel 2 (Throttle) that has the issue, so when the throttle servo is on channel 2 it swings when powered, when the steering servo is in channel 2, then then the steering swings?? So have ruled out the servo.

Zoomer, have tried a couple of different radios. FlySky FS-GT3C 2.4 & the HSP 2.4, both the same.

I have some digital servos coming, am thinking it might be an analogue servo issue. Will update when I've tried that.

Is baffling me.
 
#6 ·
Zoomer, have tried a couple of different radios. FlySky FS-GT3C 2.4 & the HSP 2.4, both the same.
so you've been seeing that response from the same ONE receiver?

safe to assume it's a FS GR3C/E/etc? :)

Are you aware it's got Failsafe & do you know how to program the Failsafe position? (RTM, there's a little button to poke.)

Reprogram the Failsafe to have both channels sit at neutral.
 
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