4G3 Rx problems

[ullberg]

I'm having the following problem with my brushless main 4G3.
After 2-3 min of flight the servos (random) goes occasionally full scale.
I hooked the heli up to an external lab power supply and found that at 3.45V this starts to happen.
As you can imagine this is a good way to crash blades as it comes without warning and really the only way I can get around it is to limit flight to maybe 2min on a 600mAh battery.

Any idea on what to try, replace the Rx (2605A)? Any advice is greatly appreciated.

Christer

[Steve Joblin]

does it happen to all the servos or just one? If it happens to all the servos, then not much else of a choice but to replace the rx... It could also somehow be the ESC, but I would start with the RX.

[ullberg]

It happens to all the servos but randomly which one.

[Steve Joblin]

You can never say for sure, but logic would say to replace the RX. Best of luck!

[Ampdraw]

Originally Posted by ullberg

I'm having the following problem with my brushless main 4G3.
After 2-3 min of flight the servos (random) goes occasionally full scale.
I hooked the heli up to an external lab power supply and found that at 3.45V this starts to happen.
As you can imagine this is a good way to crash blades as it comes without warning and really the only way I can get around it is to limit flight to maybe 2min on a 600mAh battery.

Any idea on what to try, replace the Rx (2605A)? Any advice is greatly appreciated.

Christer

I have not heard of anything like this before. Maybe disconnect the main esc and power the rx from your lab supply with one servo connected and see if you can replicate the issue with the mid 3V or maybe even lower. Try all servo ports as well as a servo in the main esc port. If you cannot replicate the issue maybe the esc or motor are drawing too much current and the rx is somehow going into some type of failsafe. Maybe the motor has a short that only is evident once it gets hot...anyway it is something quite strange but I would spend some time before you shell out the dollars for a new rx in that it works fine for the first few minutes...so to me I am thinking it may be an external influence.

Amp

[ullberg]

Thanks for the advice.

I just disconnected everything except one servo at a time and powered the rx from my lab supply. As it turns out I was wrong when I sait that is was more than one servo. It's just the elev servo! It shows the same problem in all servo ports so I guess I'll buy new servo rather than the Rx that seems to work fine.

Thanks again.

[Ampdraw]

Glad you found the issue.

Amp

[mayday1]

Originally Posted by ullberg

Thanks for the advice.

I just disconnected everything except one servo at a time and powered the rx from my lab supply. As it turns out I was wrong when I sait that is was more than one servo. It's just the elev servo! It shows the same problem in all servo ports so I guess I'll buy new servo rather than the Rx that seems to work fine.

Thanks again.

Definitely, the servo is the problem. I tested my rx2605 for low voltage operation, and it was
good down to 2.3V. At 2.2V, I have one servo moving randomly while the other two servos
were still responding to stick input.