salcrocker01

Hi Foks,

I have a strange issue:

My buddy sold me a Futaba 309DP. The throttle is on channel 3 and moves to an uncommanded position without any stick input from the transmitter. It moves from idle to about 1/3 or 30% throttle after a few seconds and stays there. I have never experienced this before with any receiver.

My radio is the Futaba 9Z WCII, which I purchased Jan 2002. I sent it to Futaba about a year ago so that they could replace a bent antenna. They looked it over after replacing the antenna and gave it a good bill of health.

After expereincing the issue with the 309DP, I called him up and he came over with a second 309DP which did the same thing. I swapped servos and that did not help. I then put my 148DP in and the uncommanded movement stopped. The antenna is running through a plastic tube that was premounted with the kit along the inside wall of the fuse, and then exits at the bottom of the airplane.

The transmitter servo page does not show servo movement when the servo jumps. I thought it maybe was a bad potentiometer, but I believe the servo page on the transmitter would show movement.

Any ideas? I would have posted this on the radio forum, but it looks like it is not being read that much.

Thanks,
Sal

muzzlemaggot

My Feedback: (7)

I'm not sure why it would do this with one type of receiver and not the other. Does it only do it while running? If so, do you have metal to metal contact on your throttle arm, causing interference?

salcrocker01

Sorry for the slow response, I was out of town.

It happens with the engine shutdown. I did speak to Futaba and he mentioned that flouresent lights can cause this to happen, the uncommanded movement that is. I took the airplane into the kitchen away from the garage and the uncommanded movement did not occur, however, the throttle servo still has the issue of 'waking up'.

To elaborate on the 'wake-up' comment:
Again this is only occuring with the 309dp and not the 148dp, both of which are on the same channel. When I have the 309DP installed and first move the throttle slowly, it doesn't move until I have the throttle at about 25-30% forward from idle. This seems to wake it up. Once it is 'awake', it operates normally. This has happened with two 309DP receivers and doesn't occur when my friend tests the receiver at his house with his 9Z version 1. I have the 9ZWCII.

My transmitter was given a clean bill of health by Futaba about a year or so ago. And, the 148DP works flawlessly. The throttle servo moves in proportion to the stick movement with immediate and accurate response.

Signed,
Perplexed!

salcrocker01

I have finally isolated the problem, but haven't completely narrowed it down. I have an Extra300XS and three servos in the tail, along with two charging jacks back there, one for the main battery and one for the smoke system. So, there are a total of five wires running back there in addition to the pull-pull rudder linkage wires. If you count the pull-pull wires then there are seven wires running to the tail of the airplane.

I decided to only hook up the throttle servo and the battery to the 309DP receiver. When I did this, voila', no problems. Then, when I plugged the rudder servo into the receiver the throttle servo started to misbehave again. The same thing with both elevator servos.

Now, I need to figure out why this is happening. I have extensions on all five of those items, both elevator servos, the rudder and both charging ports. The other thing is why is this not happening with the 148DP??? I really don't want to untie(tie-wraps) all of these items and pull servos etc. when the 148DP is functioning correctly.

Sal

captinjohn

Sal: Sure hope you find out. One of my set-ups did a simular thing...never did figure it out. I took radio out...not going to use it with a plane that needs extensions or Y,s. Capt,n

salcrocker01

Ok, Futaba said to send the darn thing in. I'm tired of fussing with it, so I'm going to send it in. They said there is no difference in the architecture of the 148 and the 309 receivers. My buddy disagrees. I give him a lot of clout since he's been continuous in the hobby for about 30years. Who knows. I'm not going to take any chances, especially with a smoke pump motor spinning around in there.

Anyhow, when I find out what the deal is I will post the answer. It's time to get that bird off the ground. I've been fooling around with it for about two months now, and it's an ARF.

Sal