bobi

My Futaba 9C is few months from being two years old.

It developed a problem today.

When i advance the throttle (ch 3 )to the top position ( wide open throttle ) the servo responds ok but after being in this position for about 30 seconds it cuts back to idle.
at first i thought i was having engine problems but it turned out to be this radio problem. I switched to another servo thinking it was a servo malfunction but this new servo also has this problem .. so the culprit must be the RX.

I came home and tried the same with my other plane using this same transmitter. Same problem exists on this setup also. so the rx is also eliminated. SO this is now a TX problem.??

Is there any feature on this radio which i might have touched by mistake and could have caused this ??

Any thoughts / advise ??

rajul

My Feedback: (58)

Doesn't sound like the problem is related to any programmable function. What's the condition of your Tx ? Did it get wet or experienced any other mishap ?

Geistware

My Feedback: (16)

If you are using a PCM receiver, the throttle will behave this way if the receiver has a low battery or the transmitter signal is lost. If this is not a PCM receiver, then I don't have any idea.

bobi

Rajul: tx is in good condition. no drop . no wet .

Geistware: thanks for your input. i checked the Battery which i flew with today and there was no light on my battery checker , i had another battery so i hooked it up -- good battery . and tried it on the plane i flew today .... no pullback on the throttle servo after 30 seconds .. so it sounds like battery weakness. I tried the new battery on second plane at home .. set up is OK>

Seems like battery problem... i am going to charge the battery tonight and see again tomorrow and give the feedback here.

and Yes..the rx is PCM type.

thanks again .. and hope this is the root of the problem.

Geistware

My Feedback: (16)

bobi, I hope this does it but if not, holler back and I will give you my 2 cents worth!

rajul

My Feedback: (58)

geistware is right on ! I forgot about battery failsafe. Guess that I never worry or think much about it ever since I hooked up a voltwatch to my Rx

Geistware

My Feedback: (16)

Rajul, I thought as you do until I had 6 digital servos on a 6 volt NiMH pack and the receiver kept going into failsafe while I was flying. Makes it hard to forget.

rajul

My Feedback: (58)

Geistware, how did you solve the failsafe problem ? Did you use a voltage regulator ?

Geistware

My Feedback: (16)

Believe it or not, I went from one 2700maH NiMH pack to one 1400maH Nicad and the problem went away! I now have two 1800maH packs in the plane for weight and balance.

bobi

I charged the batteries overnight and found out that there was no power in the battery . Looks like the battery failed . Thanks to PCM system for cutting off on throttle and forcing me to land.
If it was FM system the plane would have been flying with bad batteries and I could have lost the plane if the power was down to zero.

thanks for your 2 cents Geistware.

N i hope this info is useful for everyone on RCU>

Geistware

My Feedback: (16)

No Problem, I am glad you found the problem before it was too late!