Skarn

Ok, I’m extremely frustrated after troubleshooting an issue that should be so freaking simple for over a week now.

Here’s the deal:

I assembled a CAP 232 3d airplane. I installed 4 Eflite s60 servo’s and an Align 35am ESC. When I plug the battery in, all 4 servo’s were twitching crazily! I did have control of each servo, but when I let go of the stick, again violent twitching. So…..I was thinking of some type of interference. I moved wires to various locations…..no deal. I eventually replaced the receiver with a different one but same thing! So, I disconnected all servo’s and tried plugging them in one by one….each one twitched! I don’t think ALL 4 servo’s could be bad but was stumped. I even tried eliminating the ESC and lipo battery by plugging in a standard receiver battery directly into the receiver…same thing. So I then took everything off of the plane. When I plugged in each servo, they worked fine, no twitching! Even with all 4 servo’s plugged in, but removed from the plane, it works fine! Very weird….so I figured maybe I had somehow pinched a servo wire in the servo mount. I widened the servo mount and made a small slit for the servo wire to come through so it’s not pinched anywhere. I even replaced the rudder servo with an Eflite S75…it’s smaller and I wanted to eliminate the s60’s as a suspect. Anyway, after I reinstalled everything back into the plane, again all freaking 4 servo’s had the violent twitching!

What the heck is going on? I’m an engineer and this is really bothering me…I should be able to figure this out! The airplane is all balsa and monokote so there is no metal or carbon to interfere. I was thinking maybe static? But I have many planes with monokote and never had an issue. I’d buy all new servo’s if I thought that would help, but apparently it won’t. Any ideas?

Thanks!
Skarn

pumbadog

Just a SWAG, but if you walk away from the aircraft with your TX does the twitching go away? Some times if the TX antenna and RX antenna are too close together, the servo's will twitch.

flyer495th

Those S60 are rated for 4.8 to 5.3 vdc. What is the voltage that you esc is putting into the receiver. Have you setup the esc at all?

Skarn

Yep, I tried many varying distances...no luck.

Skarn

Skarn

I thought this too, but the standard receiver battery is 4.8v and had the same issue. The Align ESC puts out 6v....so maybe a step-down would be in order? It still doesn't explain why it happens with the 4.8v receiver battery though.....

Skarn

TFF

If on 72mhz I have had the same thing happen when forgetting to match PPM or PCM with the reciever. I also remember my 9c had an initial startup; it might need something like that done too.

Skarn

Yeah bro, I've triple checked that....it's a non-PCM receiver so I have the TX set for PPM.

Skarn

woodie

Where does your RX antenna run in relation to the servos?

Woodie

Skarn

I've run it every way I can think of. Right now it's running down the center of the bottom of the plane but not near any servo's. But even when I "unmount" the receiver and pull the antenna completely away from the plane it still happens.

Skarn

TedMo

Sounds like a real problem. It appears you have tried every normal fix without success. You say it works when out of plane but not in plane. Have you range checked it out of plane. Do you use the same tx for another plane without trouble? It certainly points to something in the plane? Are your pushrods metal also the quick links/ They should not cause any problem BUT? How about tx battery? What radio is it? 35Ma ESC should be ok but how many servos are in use? Very perplexing you seem to have given it a good shot. Would it be possible to try different freq?

TFF

I have had servos twitch from long extension runs. I twisted the wires and it went away. Old radios had the wire braided for that reason.

Skarn

Tedmo: Yes, very perplexing to me! I did not range check it out of the plane because it worked fine out of the plane. I use this transmitter for ALL of my RC planes and heli's. I'm primarily a heli guy but have flown planes with this transmitter for over 2 years without issue. Heck, I pulled the receiver and sevo's from a foamy I had that worked fine! Yes, I tried different frequencies by swapping out the receiver that had a different channel chrystal. Yes, the pushrods have metal ends and the metal quick connects....I only have 4 total servo's and this ESC is rated for way more than what I'm using...

I'm to the point of chalking it up to crappy eflite servos....but all 4 and even the s75 I put in rudder?

TFF....I have no extentions on these and all are pretty close...

Skarn

dirtybird

My Feedback: (5)

Have you tried exorcism on that airplane?

Skarn

LOL! That's what it seems it's coming down to!

TedMo

All I can say is it's heartwarming to know SOMEONE TRIES to find their problem. Can't think of anything that you haven't already done.

fizzwater2

My Feedback: (61)

You said you replaced the receiver with a different one - same type, or a completely different receiver?

flyer495th

When you replaced the reciever did you have your escape plugged into channel 3. Did you bypass the On/Off switch? I would redo these steps again to confirm earlier results one more time.

Skarn

Huh? what is an escape Do you mean ESC? The ESC plugs into the throttle channel, usually channel 1 on my JR receivers. There is no on/off switch either.

Fizz...completely different micro receiver...brand and all.

I'm going to play around again with it tonight and try everything I can think of.....again. I'll let you all know if/when I finally figure it out!

Thanks again all,
Skarn

TFF

It is the experimental iron filing paint job thats doing it.

Zeeb

My Feedback: (41)

Well I've skimmed over the posts in this thread and have not seen what radio you are using?

My experience may not be much help, but I'll tell you that the only time I experienced the issues you're talking about was either the PPM/PCM issue which has already been covered, or the other problem I ran into was that the synthesized tx module I was using (Futaba) would not play with other brand rx's, in this case neither the little JR negative shift rx's or the Hitec O5S's auto shift rx's.

While the other brand rx's seemed to work fine with the Futaba tx and a fixed frequency module in the tx, they wouldn't play with the synthesized module installed in the tx. This problem was identified initially by Hitec and finally acknowledged by the Futaba support folks here on the manufacturer's support forum and was never resolved. I never found out if it was restricted to the 9Z WCII I was using, or if it affected the 9C radio as well. I saw some reports that the 9C with a synthesized module did not have this problem and other reports saying it did have the problem. I never tried a synthesized module in my 9C Super so I can't say for sure which was the case on the 9C.

I know it's a long shot for solving your problem, but it's another case of the same issue you're currently having. I hope you get it figured out as I'll be interested in seeing what the final solution is.

Skarn

Ok, so I got so tired of trying differnt things....I just replaced all 4 servo's with the HS-55's I had in my King II and now everything works great!

Skarn

flyer495th

Could of been the S60's are rated 4.8 to 5.3 & the Hitec H55 are rated 4.8 to 6.0. Your ESC is delivering 6.0 volts to receiver.

Glad that you have resolved the problem!