Looking for Source of Servo Glitch, DSM2

[jon595]

I purchased a 12x to replace my 7 year old 10X in May 2008 along with an AR9100 Powersafe RX. It was my second DSM2 TX purchase after getting my feet wet with some smaller glow models. Approximately every 3 months since then and with this combination it will strip an aileron servo. This has happened 4 times in the course of a year. I go through the same start up procedure everytime and notice that between the time my planes power switch is turned on and it has aquired the TX signal, it will strip the aileron servo plugged into the channel 5 port. EVERYTIME I turn my radio on I confirm that the switches are all in the away positions before I turn it on. And I conduct a postflight inspection everytime.

Someone over in the 12X thread mentioned that he had an uncommanded activation of his smoke pump upon initial power up of his plane (He turns the radio on then the plane just like me).

My questions is "How many people have observed something similar to this during initial powering up of the plane".

Myself I'm trying find out because I only carry 1 plane to the field with me and it ends up ruining my day when it happens. I no longer compete with this plane for fear of it happening before a round.

My Setup: 12X using the balance function for the ailerons (no matchboxes), AR9100 Rx into 4 8611As in the wings. Ailerons have 24 degrees max deflection at 120 ATV, pushrod length is adjusted to get the same amount of throw on the surface each direction of travel. Subtrim values on the wing panel that strips the servo is LAL1 L15 and LAL2 L42. I use an ammeter to adjust the servo using the balance funtion. Those values are 0,+6,0,0,0,0,0. Max current draw is 10ma on each servo throughout the whole range of travel. I'm using the holes closest to the output shaft (all the way) in on SWB 1 1/4" servo arms. Equal distance from the hinge line (more than 1 1/4") on the factory supplied horns for the plane. Nothing is binding in the way of ball links or hitting anything when the servo goes through it's range of travel.

Back in Janurary I took out all of my electronics and wiring and shipped it along with the radio back to HH at their request. The reason that they wanted to see everything is everytime I had this problem, I called HH and talked to a tech. It's all documented under my name. Again, this has happened 4 times.

I've done everything they have asked me to do in the way of binding, rebinding, etc.

I've been an electronics tech (20 plus years aviation (military) and work for the same people as a civ) so this is not my first rodeo when it comes to troubleshooting. AND I read the manuals when setting it all up. When it all came back with a clean bill of health (they did upgrade the firmware in both the TX and RX to the latest versions) I re-installed everything in March and proceeded to use it until it stripped another servo in the beginning of June.

Troy Newman gave me a lesson and suggestions that I followed.
http://www.flyinggiants.com/forums/f...tml#post683164

I have 2 35% planes set up this same exact way. Only 1 servo location (out of 8) has this problem. Bought 2 spare 8611a servos and each of them has been in that location and each has stripped on initial start up of the plane before it is linked with the radio. So rule out the servos. The extensions in that wing panel were replaced when I put it back togeher in March. Still happened. I replaced the AR9100 RX with a 922 and have turned the thing off and on about a 1000 times since then and it has yet to happen.

My latest frustrated attempt with HH resulted in:
1. I have excessive subtrim
2. That due to the difference in servo speed (no 2 8611as will because of the motors) of the servos installed in that wing.....
3. That due to the weight of the aileron and it not being perfectly aligned upon start up.......

Kinda wished they had of told me it WAS the RX because now I feel like GS is not for me with all these new issues I've never heard of.

I was going to post this in the 12X thread but thought a new thread would be more appropriate. I'm not bashing JR or HH (maybe just a little ). Just looking into some insight about what is actually happening and if anyone else has experienced this issue.

[JohnVH]

whats it do? glitches when you turn on the tx?

[jon595]

No, TX is already on.

It glitches in between the time the RX is powered on and it connects to the TX. The servo is slaved through the balance function of the 12X. The servo is connected to channel 5 (RETRACT). Binding and failsafe set as per instructions. Takes about 3 months of use before it happens and strips the servo gears on RX power up.

[JohnVH]

and youve tried setting the ATV to 100% or less? I read somewhere that raving that set higher than 100 will make that happen... That said, only one of mine does it, a parkzone t28... I cant get it to not do it either, but It doesnt strip servo's, thats pretty frustrating I bet.

Try the JR support forum here or the other big site

[jon595]

The 12X manual tells you that the best mech. advantage takes place at 125%. I'm used to 120% so thats what I went with. I've never heard of the higher than 100% deal. Just trying to get the best servo resolution since this plane was my IMAC plane.

[JohnVH]

worth a try right? For just imac with small throws I cant see that little amount of change doing alot.. .02

[jon595]

Got it,

Thanks.

[Howard Leigh]

Jon,

It might be helpful in the troubleshooting process to know if the intial servo movement is commanded from the TX or if it is internal to the RX. Using your normal startup, turn on the TX and navigate to the "monitor" page. While closely watching the monitor page on the TX, turn on the RX and see if the monitor shows any commanded aileron movement during the data exchange between the TX and RX.

If the monitor does not show a command to move the aileron then I would think that the troubleshooting should concentrate on those functions driven by the receiver - even if the receiver might be getting it's info from the TX such as in failsafe. (I think)

One last thoght (my apologies if you have already covered this ground) can you reassign the affected aileron to a different channel and see if that make the issue go away. That would not fix the root cause but, it would be another troubleshooting clue.

Good luck.

Howard

[bodywerks]

	Quote:
	Someone over in the 12X thread mentioned that he had an uncommanded activation of his smoke pump upon initial power up of his plane (He turns the radio on then the plane just like me). My questions is "How many people have observed something similar to this during initial powering up of the plane".

When you bind the tx to the rx all switches and stick positions need to be in the correct position at the time of binding. And if, once bound, you find that certain channels are reversed and you have to correct them, YOU MUST RE-BIND.
So what happened with the guy who's smoke pump came on momentarily is that his smoke switch was either in the on position when he binded or the channel that operates the smoke was reversed.

[bodywerks]

	Quote:
	I re-installed everything in March and proceeded to use it until it stripped another servo in the beginning of June.

Have you considered that maybe your problem is a servo problem?? My buddy has stripped no less than a half-dozen(maybe more) 8711A's on the ailerons of his 150cc Yak over the course of a little over a year. We set our servos up the same as you, with an ammeter, and they are nearly perfect throughout the full range of travel. We have basically just accepted the fact that after about 50-60 flights he will need to have a spare servo in the ready box because one of them are about to fail. Sucks that we have to think like this with $125 servos...

[bodywerks]

Sorry, I'm reading your posts as I respond, but:

	Quote:
	The servo is connected to channel 5 (RETRACT)

Now, I don't have the 12X, but I do use channel 5 for my slave elevator on my 9303(I don't use the 'dual elevator' function - I use a multipoint mix), and since the retract switch cannot be inhibited, the switch command is either full up or full down(in gear terms). So in order for channel 5 to work as a slave I have to set its ATV to zero. Otherwise, if I inadvertently flip the gear switch it would cause one of my elevator halves to move!!!
Just wondering if this could be an issue for you and maybe your retract switch is in the other position when you go to turn the plane on and the servo strips??? If it is only channel 5 that is stripping servos I would say that it would be worth giving it a try to put that servo on another channel.

[bodywerks]

	Quote:
	Ailerons have 24 degrees max deflection

Off topic, but how can you get crisp snaps with only that much aileron throw? I fly with 33 degrees at all times and would still like the snaps to be a tad faster...

[jon595]

	Quote: Originally Posted by bodywerks
	When you bind the tx to the rx all switches and stick positions need to be in the correct position at the time of binding. And if, once bound, you find that certain channels are reversed and you have to correct them, YOU MUST RE-BIND. So what happened with the guy who's smoke pump came on momentarily is that his smoke switch was either in the on position when he binded or the channel that operates the smoke was reversed.

It was RE-BOUND, still happened. Troy Newman offered up some info back in Jan. of this year when I was trying to correct this problem on servo #3. His was on the retracts.

When it strips a servo all I do is put a back up in, and readjust subtrim, and the balance function for the left aileron. It will get re-bound but give it 3 months and it will do it again.

[3D-Seth]

Have you tried holding the ailerons centered with your fingers when you power on? That way they don't have to "glitch" themselves to center?

I run the same setup (AR9100, JR 12X) on my 120" QQ Yak with no issues...

[jon595]

	Quote: Originally Posted by bodywerks
	Have you considered that maybe your problem is a servo problem?? My buddy has stripped no less than a half-dozen(maybe more) 8711A's on the ailerons of his 150cc Yak over the course of a little over a year. We set our servos up the same as you, with an ammeter, and they are nearly perfect throughout the full range of travel. We have basically just accepted the fact that after about 50-60 flights he will need to have a spare servo in the ready box because one of them are about to fail. Sucks that we have to think like this with $125 servos...

The servo was not stripped at the end of a flight, I always check (post flight insp). It happens in between the time it powers up and links to the TX signal.

If it happened on any other aileron servo position I would buy the servo issue.