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cowboysir
2011.12.10, 08:10 PM
Hi,

Its not an aftermarket chassis so much as I'm building a modular electronics MR02 for a friend of mine who wants to use his spectrum DX2R Tx:

I had a Futaba servo board and wired in the pot and motor leads to said board. Besides having the steering reversed and having to use all my controller function to center the MR02 servo arm I'm getting a weird servo "bouncing" effect where when i release the TX wheel for a quick steering center it judders back and forth for a good couple seconds...

Is it because I used a Li-po pack (7.4volts) to test for function or has anyone else experienced this problem?

I'm going to try swapping the motor leads around for the servo direction correction (and hopefully get some of the servo centering situation figured out) but if someone can let me know if the test voltage was my issue for the juddering/bouncing I'd appreiciate it.;)

thestug
2011.12.10, 08:47 PM
Hi,

Its not an aftermarket chassis so much as I'm building a modular electronics MR02 for a friend of mine who wants to use his spectrum DX2R Tx:

I had a Futaba servo board and wired in the pot and motor leads to said board. Besides having the steering reversed and having to use all my controller function to center the MR02 servo arm I'm getting a weird servo "bouncing" effect where when i release the TX wheel for a quick steering center it judders back and forth for a good couple seconds...

Is it because I used a Li-po pack (7.4volts) to test for function or has anyone else experienced this problem?

I'm going to try swapping the motor leads around for the servo direction correction (and hopefully get some of the servo centering situation figured out) but if someone can let me know if the test voltage was my issue for the juddering/bouncing I'd appreiciate it.;)

I know the steering on a mini-z gets a little wierd when trying more than 6.6V. I think. Is it just the steering wheel boncing back and forth when you release the wheel. When I release any of my wheels to return back to center they cause the wheel to vibrate for a second or two.

cowboysir
2011.12.11, 10:27 AM
mini-z electronics have nothing to do with this.

Has anyone found that Futaba micro servos have a juddering issue at 7.4 volts or have I got something wired wrong?

If it comes down to it I guess I'll have to swing together a 4.8volt pack and test but I had hopes someone would have some enlightening info.:o

color01
2011.12.11, 06:49 PM
Were you using an older (S311x) Futaba servo PCB? Those things are just junk, I only used the S3114 in the MRCG because the rest of it (the geartrain/pot/motor combo) was decent and easily replaceable.

Larger servos' PCB's will have an easier time handling 7.4V, what with LiPo racing and all nowadays. Good luck fitting the larger PCB into an MR02 though...

cowboysir
2011.12.11, 08:24 PM
I couldnt dial the bouncing all the way out on 4.8volt. It got a little better once I turned down the return rate on the steering speed function but never quite got it to work flawlessly.

took a pcb from a Hitec hs55 and its all good now;)

TheSteve
2011.12.31, 04:43 AM
The problem you had is related to the feedback loop in the servo controller. In your case the motor was moving the pot faster then the servo controller could read the position and change the drive to the motor.