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clammster · 09-27-2008, 09:27 PM

Well started yesterday, flew and tail went crazy, landed and found my JR8417 wasn't working just buzzing and not accepting inputs.
So a gear set wasn't available so I got a 8900G tail servo, works great.
Go to fly today, All the sudden my throttle isn't going very high and i have no pitch control.
so used what throttle I had to land safety, now my throttle servo is working however full throw is only about 1/4", and my pitch servo is now buzzing and not working at all. pitch servo is also jr 8417. Those are expensive servos to keep frying, I need to figure out what the heck is going on.
I took both JR servos apart and see no broken gears.

Im so frustrated, i just got the thing used and flew it, it flew well for one day, i can't figure out what I am doing wrong if anything.

Advice needed

Badger50 · 09-28-2008, 09:39 PM

Sorry to hear about your problem Clammster. I don't know if I can help, but I'll try. What voltage are you running, sounds stupid, but as I've come to find out in this hobby, there are no dumb questions. Are the sevos shock mounted? Check all of your wiring, are there any cuts in lines, or somewhere where there might be a short? Is the receiver old, new, and are you using FM, PCM or 2.4gz frequency, sometimes ultrasonic vibrations can play hell with electronis. Have you had any hard landings or crashes? Is the motor well tuned, again the vibration thing. Are the blades and flybar paddles tracking good? Again, the vibration thing. Maybe you got a couple of lemons for servos, believe me it happens. I bought a brand new truck earlier this year, and the very next day, the transmition went out, so nothing is out of the rehlm of possibility. Give your heli a very good "once over" and look for any metal screws, skids, or contact points that could cause ultrasonic vibrations, you would be amazed at what those little gremlins can do. Other than that, thats all I can help you with. Let us know anything you find out. Good luck

clammster · 09-29-2008, 06:42 AM

I appreciate your help. Im running 2.4. It flys smooth, the head was setup by me and then gone over by another pilot, then yet another guy who does it for a living. Everyone said it was good. Blades in track. When my battery is fully charged im showing 5.3V DC. Receiver is new btw. No hard crashes, but the heli was used. It did fly fine after I bought it for about 1 flight, then I started running into problems. I suspect some of it could have been the heli getting banged around in the car, or maybe I forgot to unlock the blades when turning it on. Im really not sure. What I have decided to do is take all servos out including the 2 bad ones and send back to horizon for evaluation. Hopefully they can shed some light on what happened. I was really hoping when I disassebled the servos that it would be a gear set, but that wasn't the case.

Keep the ideas coming. I cant find any shorts anywhere, all wires look clean.

Quote:

Originally Posted by Badger50

Sorry to hear about your problem Clammster. I don't know if I can help, but I'll try. What voltage are you running, sounds stupid, but as I've come to find out in this hobby, there are no dumb questions. Are the sevos shock mounted? Check all of your wiring, are there any cuts in lines, or somewhere where there might be a short? Is the receiver old, new, and are you using FM, PCM or 2.4gz frequency, sometimes ultrasonic vibrations can play hell with electronis. Have you had any hard landings or crashes? Is the motor well tuned, again the vibration thing. Are the blades and flybar paddles tracking good? Again, the vibration thing. Maybe you got a couple of lemons for servos, believe me it happens. I bought a brand new truck earlier this year, and the very next day, the transmition went out, so nothing is out of the rehlm of possibility. Give your heli a very good "once over" and look for any metal screws, skids, or contact points that could cause ultrasonic vibrations, you would be amazed at what those little gremlins can do. Other than that, thats all I can help you with. Let us know anything you find out. Good luck

Lota Fun R · 09-29-2008, 05:02 PM

5.3v ?

I use a 7v lipo battery and at full charge it's at 8.2v

vandelescrow · 09-29-2008, 05:10 PM

5.3v is correct on a 4.8v pack. I'd check for binding on the servos. I did not read your entire post but did you get it used or has it been in a crash?

clammster · 09-29-2008, 07:27 PM

got it used, rebuilt and set up from scratch. No binding. smooth operations, and i did have a few good flights before things acted up.

Quote:

Originally Posted by vandelescrow

5.3v is correct on a 4.8v pack. I'd check for binding on the servos. I did not read your entire post but did you get it used or has it been in a crash?

clammster · 09-29-2008, 07:29 PM

Really, my gyro wont handle that voltage. Anyway, the voltage is correct for my gyro/servos.

Keep any advice coming

What I decided to do, is set it aside. I don't want to throw money at the problem, and let emotion get the best of my wallet. So I took all the servos out and sent them to JR for eval.

So that will probably cost 150.00 or so. Each servo is about 120.00 so to me its worth it.

Then in the eval, maybe they will be able to determine what the possible causes were.

Quote:

Originally Posted by Lota Fun R

5.3v ?

I use a 7v lipo battery and at full charge it's at 8.2v

Lota Fun R · 10-01-2008, 03:31 AM

One of my heli's has align 2 in 1, so that puts voltage at 6, stepped down to gyro and throttle servo. the other has a 7100R rec, the rec runs lower voltage to the gyro and at the same time runs the cyclic servos at 8v. (pack voltage).

Even though the battery puts out more than required, I would think a battery at only 5.3v is low and I wouldn't even try to use it.

All my flight batteries put out 8.2 fully charged.

I would say that your pack voltage is something I would be suspect of.

Maxime30 · 10-10-2008, 10:17 PM

Just another idea even though I know it's too late...

Are the servo arms genuine JR arms? A wrong servo arm (or a damaged one) can strip and even though the servo works correctly the servo arm won't follow the servo movements...

Just an idea...

clammster · 10-11-2008, 06:31 AM

Thanks for the reply. The arms are actually genuine JR arms. In fact the servos dont act right without the arm attached at all.

Keep em coming.

Quote:

Originally Posted by Maxime30

Just another idea even though I know it's too late...

Are the servo arms genuine JR arms? A wrong servo arm (or a damaged one) can strip and even though the servo works correctly the servo arm won't follow the servo movements...

Just an idea...

RotaryBliss · 10-11-2008, 08:47 AM

Taking into consideration that the heli was used with no rx, assuming the servos came with it? perhaps the previous owner ran them at too high a voltage long enough to put them on the brink of failing? Then dropping them to a proper voltage and using them causing them to fail. Do you know this person well?

clammster · 10-11-2008, 07:07 PM

Not that well, it had a 4.8v pack that was included they said they flew it with, but we don't know that for sure, thats while I pulled all servos and sent back for evaluation.

Quote:

Originally Posted by RotaryBliss

Taking into consideration that the heli was used with no rx, assuming the servos came with it? perhaps the previous owner ran them at too high a voltage long enough to put them on the brink of failing? Then dropping them to a proper voltage and using them causing them to fail. Do you know this person well?

09-27-2008, 09:27 PM	#1 (permalink)
clammster Registered Users Join Date: May 2008	JR Servo's in rap 60 getting taken out please help Well started yesterday, flew and tail went crazy, landed and found my JR8417 wasn't working just buzzing and not accepting inputs. So a gear set wasn't available so I got a 8900G tail servo, works great. Go to fly today, All the sudden my throttle isn't going very high and i have no pitch control. so used what throttle I had to land safety, now my throttle servo is working however full throw is only about 1/4", and my pitch servo is now buzzing and not working at all. pitch servo is also jr 8417. Those are expensive servos to keep frying, I need to figure out what the heck is going on. I took both JR servos apart and see no broken gears. Im so frustrated, i just got the thing used and flew it, it flew well for one day, i can't figure out what I am doing wrong if anything. Advice needed

09-28-2008, 09:39 PM	#2 (permalink)
Badger50 Registered Users My HF Map location Join Date: Oct 2007	Sorry to hear about your problem Clammster. I don't know if I can help, but I'll try. What voltage are you running, sounds stupid, but as I've come to find out in this hobby, there are no dumb questions. Are the sevos shock mounted? Check all of your wiring, are there any cuts in lines, or somewhere where there might be a short? Is the receiver old, new, and are you using FM, PCM or 2.4gz frequency, sometimes ultrasonic vibrations can play hell with electronis. Have you had any hard landings or crashes? Is the motor well tuned, again the vibration thing. Are the blades and flybar paddles tracking good? Again, the vibration thing. Maybe you got a couple of lemons for servos, believe me it happens. I bought a brand new truck earlier this year, and the very next day, the transmition went out, so nothing is out of the rehlm of possibility. Give your heli a very good "once over" and look for any metal screws, skids, or contact points that could cause ultrasonic vibrations, you would be amazed at what those little gremlins can do. Other than that, thats all I can help you with. Let us know anything you find out. Good luck __________________ Mike: Rap-90 3D x 2, Rap-50 x 2, Fury 55, Rex-450, Hirobo Squark. *"Depression is nothing more than anger, without enthusiasm"*

09-29-2008, 05:10 PM	#5 (permalink)
vandelescrow Registered Users My HF Map location Join Date: Sep 2006	5.3v is correct on a 4.8v pack. I'd check for binding on the servos. I did not read your entire post but did you get it used or has it been in a crash? __________________ Lord let me be the person my dog thinks I am.

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09-29-2008, 05:02 PM	#4 (permalink)
Lota Fun R Registered Users Join Date: Aug 2007	5.3v ? I use a 7v lipo battery and at full charge it's at 8.2v

10-01-2008, 03:31 AM	#8 (permalink)
Lota Fun R Registered Users Join Date: Aug 2007	One of my heli's has align 2 in 1, so that puts voltage at 6, stepped down to gyro and throttle servo. the other has a 7100R rec, the rec runs lower voltage to the gyro and at the same time runs the cyclic servos at 8v. (pack voltage). Even though the battery puts out more than required, I would think a battery at only 5.3v is low and I wouldn't even try to use it. All my flight batteries put out 8.2 fully charged. I would say that your pack voltage is something I would be suspect of.

10-10-2008, 10:17 PM	#9 (permalink)
Maxime30 Registered Users My HF Map location Join Date: Nov 2007	Just another idea even though I know it's too late... Are the servo arms genuine JR arms? A wrong servo arm (or a damaged one) can strip and even though the servo works correctly the servo arm won't follow the servo movements... Just an idea...

10-11-2008, 08:47 AM	#11 (permalink)
RotaryBliss Registered Users Join Date: Sep 2008	Taking into consideration that the heli was used with no rx, assuming the servos came with it? perhaps the previous owner ran them at too high a voltage long enough to put them on the brink of failing? Then dropping them to a proper voltage and using them causing them to fail. Do you know this person well?

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