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Old 08-11-2009, 05:52 PM   #1
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Default jr 9100t

i have a problem with my jr 9100t
with the wheels off the ground the wheels shake i think its trying to find center. when its on the ground its stops somtimes. what do you guys think i have to do to fix it or should i replace it

and if i have to replaced it what servos should i look into buying ??
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Old 08-11-2009, 05:58 PM   #2
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I've got the same problem with 2 of the same servos, I used to run them on our crawlers, that was when they did the wiggle....but after installing them on the losi 2.0 buggy i have not had an issue for about 3 months..id say run them till it gets worse then send them in for repair...
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Old 08-11-2009, 05:58 PM   #3
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Quote:
Originally Posted by dadsvtechonda View Post
i have a problem with my jr 9100t
with the wheels off the ground the wheels shake i think its trying to find center. when its on the ground its stops somtimes. what do you guys think i have to do to fix it or should i replace it

and if i have to replaced it what servos should i look into buying ??
Thats called the JR Jitters. My 9100's do that too. It is exactly that they are digital and trying to find the center. You wont notice anything while racing or driving. I have been told thats normal for these servos.
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Old 08-11-2009, 06:10 PM   #4
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Thats called the JR Jitters. My 9100's do that too. It is exactly that they are digital and trying to find the center. You wont notice anything while racing or driving. I have been told thats normal for these servos.
i hope so
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Old 08-11-2009, 06:10 PM   #5
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i've had both of mine in steering with no jitters, maybe some grease or water ran down onto th cirsuit board?
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Old 08-11-2009, 06:10 PM   #6
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The inside of the top case is cracked or broke where the center gear shaft is supported. It causes too much play so the servo can't find center.

You can send it back to JR and they will repair it, they have a 3 year warranty.
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Old 08-11-2009, 06:28 PM   #7
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It's just like the futaba jitter problem.

The first gear has most likely gotten wore out or lost a couple of teeth and can't find its center. Check your first gear since it is usually plastic or metal its the weaker gear and will take most of the stress from the drive train.

The problem is fine "only" if you are getting the jitters when there is no pressure on the wheels. If it starts to get worse and does it while on the ground its time to send it in.

I believe the 9100t/s are both plastic 1st gears and they didn't change this until they release the 9100t/s HV servos.
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Old 08-11-2009, 07:06 PM   #8
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I just had Horizon send me a new set of gears for my 9100s, my problem was caused by the 2.0 servos saver having no give and it wore the gears down fast. I've had this issue in my giant scale airplanes (10 years ago when digital servos came out) the control surface was heavy enough to cause the same issue. In all thoes instances, the gears had play. So I knew what happined when my 9100s started the "shakes".

oh yea, i went to the 1.0 servo saver.
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Old 08-11-2009, 09:05 PM   #9
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Mike they are telling you exactly what I told you at the track. It is either the top servo case has cracked where the center bushing is or gear B is bad. You can now buy the gear B by itself (the gear is half metal & plastic) part number is JRPSGB4 for about $7.

I had a 9100s do this after two weeks of racing. I have since sold that servo after finding the top case cracked and replaced it with a Futaba servo.
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Old 08-11-2009, 09:20 PM   #10
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The 1.0 Saver is a for the Losi is now a running change on all the Rollers and RTR's.

They went back to the 1.0 plastics, but kept the spring. Spring was never and issue. The plastics on the 2.0 were cut to deep and were binding the plastics.
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Old 08-11-2009, 09:34 PM   #11
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Know of a couple guys that have this same issue,

I have a 9100T that has 3 season on it and it just now showing the signs described. Good to know it could be just a gear that can be replaced. I'll let a few guys know that. I swapped mine out to my other new one just in case
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Old 08-11-2009, 10:23 PM   #12
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Quote:
Originally Posted by jrwoodchuck View Post
I just had Horizon send me a new set of gears for my 9100s, my problem was caused by the 2.0 servos saver having no give and it wore the gears down fast. I've had this issue in my giant scale airplanes (10 years ago when digital servos came out) the control surface was heavy enough to cause the same issue. In all thoes instances, the gears had play. So I knew what happined when my 9100s started the "shakes".

oh yea, i went to the 1.0 servo saver.
I had a 9100 do this on my 2.0 and everyone said it's just how some servos get. It didn't affect the operation other than being annoying when the buggy was on the bump box and the wheels were off the ground.

A few weeks after that I was doing a partial re-build to check for problems and found the bottom collar of the servo saver had worked it's way out so that it was dragging the mount pole. I fixed that as I put everything back together, and the servo jitter was gone. I do think that having a bit of drag in the steering assembly at any point can cause this, so you might check that first.
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Old 08-12-2009, 05:25 PM   #13
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If your 9100t is jittering take the top case off and take a look at the plastic around the bronze bushing that holds the center gear support post. Most likely it is ovalized causing play in the gears. To fix it get JRPSC8611 it is the same top case as the 9100t and only about $8. This is also a good piece to keep for spare in case your ever break a servo ear.
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Old 08-12-2009, 06:27 PM   #14
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I had an issue with my 9100S and 9000s that was similar. I was told it was because I was using a speed servo instead of a torque servo after trying several receivers. Then I tried different servos and they were doing the same damn thing, even old analog servos, (yeah I adjusted to 11ms framerate)

Then I switched my DX3R to show the monitor and discovered that my radio was the culprit. The monitor was going crazy on the throttle, from positive to negative travel for no reason. I installed a DX2.0 receiver and radio and the glitch completely disappeared.

From what I understand, JR servo's are bad about these glitches, but make sure you rule out the radio as well!
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