Carbsmart -servo jittering!!

[J-S-Q]

I have recently fitted a carbsmart and I noticed yesterday that just after landing, the mixture servo was jittering very fast, back and forth by a small amount -maybe 1-2 mm. This seemed to stop after about 20 seconds or so. Has anybody had this happen. Guess it could be a bad servo but it's the only one I have on hand at the moment.

Any thoughts?

Thanks.

[forjer]

Did you remove the clicker from the needle? If not, give that a try. It could be causing too much resistance for your servo to relax after commanding a move.

[J-S-Q]

Yes, I have taken it off and the needle has very little resistance when you turn it without the servo connected.

[stmpngrnd]

mine does that on startup for about 10-15 seconds and then stops.

[J-S-Q]

Does is stop as the engine heats up? Or does it just stop anyway even if the engine is not started? Seems a little strange.

Have you managed to confirm that it's doing it's job properly, i.e. with a data logger, or visual confirmation of the needle being moved in flight? I'm too much of a beginner to hover close enough to see.

[forjer]

What servo and how much use has that serve seen prior to installing it for the C.S.? Do you know if it does this only at the extreme end of travel or does it jitter towards the meddle too? If just at the end, could it be a weak servo and it just works too hard to get to that extreme end of travel? If so you could change the limits a tiny bit so it's not turning so far to see if that eliminates the jitters.

[TheBum]

Did you make sure you dialed your gain down to 50% after setting the throws? A too-high gain might cause such jittering.

[Y@nkee]

Mine is jittering on power up to, but only for 2-3 secs, if i manually set it to anything else than full lean before powering up, it will just go to full lean with no jitttering when powering up.
Mine is a brand new HS65HB

[stmpngrnd]

Does is stop as the engine heats up? Or does it just stop anyway even if the engine is not started? Seems a little strange.

Have you managed to confirm that it's doing it's job properly, i.e. with a data logger, or visual confirmation of the needle being moved in flight? I'm too much of a beginner to hover close enough to see.

HS 81 servo and yes it stops jittering after a few seconds BEFORE I start the engne. It is doing its job via visual inspection and the fact that my engine is now running better than ever before.

[J-S-Q]

What servo and how much use has that serve seen prior to installing it for the C.S.? Do you know if it does this only at the extreme end of travel or does it jitter towards the meddle too? If just at the end, could it be a weak servo and it just works too hard to get to that extreme end of travel? If so you could change the limits a tiny bit so it's not turning so far to see if that eliminates the jitters.

It's a micro servo that came with a Spektrum DX6. It saw light use in my Trex 450. The jiter does only happen at the extreme of travel. I have just adjusted the endpoints on the Carbsmart and made them a touch lower and I think I may have solved this issue but perhaps this servo needs replacing in the long run as I'm sure the jitter wasn't happening when I first set up the carbsmart. Interesting that Y@nkee is getting this problem with a brand new HS65. And yes, by the way, the gain is set to about 50%.

Any particular servos that are recommended for use with the Carbsmart.

Thanks everyone for the input.

[floop]

on mine the jitter was caused by the lean endpoint being to far out. Reset the carbsmart with the full lean and rich settings a little less than full servo throw.

[bacala600]

I have a new HS56HB in my heli, it jitters for a few secs on power up but I never tried to correct this its works great in flight

[forjer]

I've been using an HS-55. No complaints yet. I'm probably not using as much throw as I would with a stronger servo though.