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JR servo chatter

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Old 12-10-2002, 04:19 AM
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dleppard-RCU
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Default JR servo chatter

I've got a JR servo that is a number of years old now and has given excellent service to date. The model number came off a couple of years ago, and I don't remember what it was, but the servo is metal-gear, coreless, and high speed. I remember that it had 88in.oz of torque.

The problem is that it has begun to chatter, as a servo does when it's under load pretty much all the time when it is sitting a neutral. It's possible to get it to stop by putting a little pressure on the surface it's attached to in the direction away from the one that is causing the chatter, but as soon as you move the sticks and it returns to neutral it will begin to chatter again. The chatter is not consistent, but pretty much always there.

My questions are: What is likely wrong? What is required to fix it? What kind of cost is likely to be involved? Is it worth fixing?

Other than the chatter it still works well.

Thanks,

Dave Leppard
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Old 12-10-2002, 01:53 PM
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Default JR servo chatter

It may be a worn pot in the servo, or maybe worn gears. It may be worth fixing if it works fine other than the chattering. I would say when you get a chance, send it in to our service center and request a quote in your letter and they can let you know how much it will cost.
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Old 12-10-2002, 02:40 PM
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Default JR servo chatter

Danny,

How long to the pots last? I didn't realise they were prone to wearing out. Do higher quality servos like the 8411 have better pots than a 531? How do I determine when to throught the cheaper servos out or have the better ones fixed?

Should they be cleaned every year with some tuner cleaner to increase their life and reliablity?

Thanks again,

ML
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Old 12-10-2002, 03:29 PM
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Default JR servo chatter

Generally they will last a very long time, usually several years. There isn't a rule of thumb on this though. The pots are all about the same without any differences in them that would make one last longer than another. If you start to notice any problems with them, or if they change the way they are working is about the only indication. It is not a bad idea to clean them out with some silicon based electric cleaner, but depending on how often you fly, every year is not really required, and most of the time, the pot will likely wear out before it is required to be cleaned.
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Old 12-10-2002, 06:43 PM
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Default JR servo chatter

Dear Danny,

Thanks for the response. It sounds like I could give it a try servicing it myself by using some pot cleaner, seeing if that makes the difference, and then trying some new gears and seeing if that does it.

One note on the gears: There is some definite play in the gear train. It is about the same as that of a cheaper servo like a Futaba 148. The train is not tight like the newer all metal gear train hitec digitals I own. Does this imply wear on this particular servo?

Finally, could you give me the model number for the servo I described?

Thanks,

Dave
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Old 12-10-2002, 07:08 PM
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Default JR servo chatter

Metal gears do commonly have more slop than a servo with nylon gears. If the slop has increased it is wear, but it is difficult to say with the info given. I don't see a servo listed with those exact same specs. Is it a standard size servo, how old is it, do you have any other info on it?
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Old 12-10-2002, 07:14 PM
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Default JR servo chatter

Thanks.

It is a standard sized servo. The only thing I remember for sure is the coreless, high speed (I think maybe .12 ms.). I saw a listing for it from Horizon, I think, maybe three years ago. As I recall the price was about $90. Don't know if this will help.

Dave
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Old 12-16-2002, 02:14 PM
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Default JR servo chatter

My best guess is a 4735 with the metal gear train installed.
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