Twitchy Servos

[Destin]

I'm Just starting my electronics testing and have found my Futaba servos are acting twitchy.

I am using:

Phoenix 80 ESC (setup as described in my other recent post)
Spektrum AR7000 RX
Spektrum DX7 TX
Futaba GY-401 Gyro
Futaba 9254 Rudder Servo
Futaba 9452 Cyclic Servos

I have programmed the ESC, and bound the TX to the RX. I do get movement from the servos, but I notice if I make sudden motions on the stick, the servos make wild and sporadic jumps - definitely not something it should be doing while flying!

The TX is a brand new program. I setup for a helicopter 3 servo 120 degree with Gyro on the gear channel. No other changes to the TX program, yet.

Please help!

[LITHIUMSTATIC]

It has a 120 degree swash. Go into your swash type and make sure it's 120 degrees.

[Destin]

Oops - typo - indeed it is set to 120 degree swash.


Maybe I should also mention I am powering off the built in BEC from the Phoenix ESC. Is it possible this servo configuration needs more power than the BEC is giving? Just a guess... I notice the ESC gets very warm (even hot) in just a few minutes ... and the motor isn't event connected. Is that normal?

The behavior I am seeing is BIG shifts in the servo positions. For example, the arms (more than 1 is doing it) will jump down 45 degrees and back up to where it should be.

I made sure my TX isn't too close to the RX... I don't know... I'm just grasping at straws now.

[LITHIUMSTATIC]

What is your main battery pack?

[BruceW]

Use the RX battery pack instead on the battery channel (unplug the ESC) and see if you get the same behavior. I had a case where a WR 5A BEC caused that problem with a PCM radio.

[Destin]

I am using a 6S LiPo 3700mAh battery.

Unfortunately I dont have an RX battery for testing at the moment.

The Futaba 9452 servos are listed as requiring 6V - but I cant find anywhere in the Phoenix manual as to what it is supplying. I remember setting the output voltage on my Align ESC for the Trex for 6V - I guess this ESC does not have such a setting.

[LITHIUMSTATIC]

Phoenix 80 specs

Volts w/BEC 12.6 max
Volts NO BEC 25.2 max
Lipo Cells w/BEC 3S max
Lipo Cells NO BEC 6S max

Are you running a 6s Lipo and trying to use the built in BEC??? If so you can't because the Castle 80 only allows use of the built in BEC if using a 3s Lipo or less.

[LITHIUMSTATIC]

You need http://www.readyheli.com/Western_Robotics_Hercules_5amp_5_AMP_Battery_Elimi _p/wrl-hbechc.htm

Good news is that it's on sale and works awesome!!

[Destin]

Thanks! You are the man!

At least I was on the right track as to what the problem might be...

Is there a chance I broke something plugging it in, you think?

[BruceW]

I have a WR 5A BEC I'm trying to sell thats never been used. If interested I can get it in the mail tomorrow. PM me if interested.

[LITHIUMSTATIC]

Is there a chance I broke something plugging it in, you think?

I doubt it since it wasn't under a load. Buy Bruce's BEC... You won't regret it.