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Lighthorse · 05-29-2021, 06:16 PM

Everything is set and ready to go except the tail servo. Gyro response is correct, Direction is correct. end points are set. BUT it will not center.
on powerup the tail will go hard left or right. just not center.

receiver,
Spectrum AR7200BX.
I have checked all setting numerous times, I cant find the problem.
Any ideas?

Gyropilot · 05-29-2021, 09:39 PM

Lots of questions are needed to properly diagnose this…

How are you programming the AR7200BX? On the device itself or are you using StudioX software?

Please tell us everything about your tail servo… brand, model, frequency, center pulse width, etc.

When you say “the tail will go hard left or right” do you mean the tail will randomly go to full left or right after the AR7200BX initializes? Does it stay there?

Once it goes to full deflection like that, can you still move the tail servo with your transmitter? If yes, what happens to the tail servo when you center the rudder stick again after moving it?

John L.

Cyclone7 · 05-30-2021, 01:35 AM

I would first check that the correct servo centre pulse width and rudder servo frequency for the servo in question, have been used in the set-up.

Lighthorse · 05-30-2021, 07:13 AM

Trying to setup for a friend.
SAB 770
Spektrum iX12
AR7200BX (No link cable or box, stock) 1 is 2+ center, 2 is 2+ center, 3 is 3+ center
Castle Edge 160
Torq BL9188 Tail servo (pulse 760 Frequency 333)
Quantum 4530-500

On spool up, the tail flies to the right, so I changed normal throttle curve to 0-100 and tried to spool up as slow as possible, no luck, barely had time to drop throttle. On the bench the Gyro is reacting the way it should, the tail rotor is spinning the right way. left and right are correct.
As for centering the rudder, I can on the bench if I gently ease it over but if I just move the stick it immediately travels hard left or if I try the other direction goes full right.
I can't slow the travel down or make it at least respond to stick controls properly.
Everything else is working properly and set right.

Morrchew · 05-30-2021, 08:45 AM

Make sure that FBL orientation is correct

sutty · 05-30-2021, 10:39 AM

760us is not that uncommon now, but it's not the default. It is essential that you change the appropriate set-up step to the correct setting.

The symptoms you describe sound much like what you would expect if it were incorrect. Do not keep trying it until you are certain, as unless the servo has built in protection, it can drive it hard over, lock up, and burn out.

Disconnect the lead, make the correct setting for 760us, and 333Hz, or even 560Hz, if you like, since that's the setting recommended on the MB website. 333Hz would be fine though, and would be gentler on the servo.

Repeat any other tail set-up steps.

Gyropilot · 05-30-2021, 11:09 AM

That’d be my first guess also… that the center pulse width of the servo isn’t correct.

Do you know what version firmware is in the AR7200BX? I believe the last available for that model was 4.0.14.

John L.

Lighthorse · 05-30-2021, 12:09 PM

OK guys got it, not being used to Spectrum I needed to set the gyro settings.
she is now flying. it was locked in heading lock. I needed to set to rate mode.
Thanks again.

Gyropilot · 05-30-2021, 02:55 PM

Glad you figured it out and thank you for posting what you found. It helps all of us learn.

John L.

05-29-2021, 06:16 PM	#1 (permalink)
Lighthorse Registered Users Join Date: Mar 2020 Location: Addison, ME.	Tail servo bad response Everything is set and ready to go except the tail servo. Gyro response is correct, Direction is correct. end points are set. BUT it will not center. on powerup the tail will go hard left or right. just not center. receiver, Spectrum AR7200BX. I have checked all setting numerous times, I cant find the problem. Any ideas?

05-29-2021, 09:39 PM	#2 (permalink)
Gyropilot Registered Users Join Date: Dec 2014 Location: SE Arizona, USA	Lots of questions are needed to properly diagnose this… How are you programming the AR7200BX? On the device itself or are you using StudioX software? Please tell us everything about your tail servo… brand, model, frequency, center pulse width, etc. When you say “the tail will go hard left or right” do you mean the tail will randomly go to full left or right after the AR7200BX initializes? Does it stay there? Once it goes to full deflection like that, can you still move the tail servo with your transmitter? If yes, what happens to the tail servo when you center the rudder stick again after moving it? John L. Cyclone7 likes this.

05-30-2021, 10:39 AM	#6 (permalink)
sutty Registered Users My HF Map location Join Date: Feb 2008	760us is not that uncommon now, but it's not the default. It is essential that you change the appropriate set-up step to the correct setting. The symptoms you describe sound much like what you would expect if it were incorrect. Do not keep trying it until you are certain, as unless the servo has built in protection, it can drive it hard over, lock up, and burn out. Disconnect the lead, make the correct setting for 760us, and 333Hz, or even 560Hz, if you like, since that's the setting recommended on the MB website. 333Hz would be fine though, and would be gentler on the servo. Repeat any other tail set-up steps. __________________ Regards, Sutty BeltEXI, mCX, mSR, 4G3, FBL Trex250SE µB, FBL Trex450Pro µB, FBL Trex550e VX1 Pro, FBL Trex600ESP VX1e, Parkzone P51D, QRX350Pro

05-30-2021, 12:09 PM	#8 (permalink)
Lighthorse Registered Users Thread Starter Join Date: Mar 2020 Location: Addison, ME.	OK guys got it, not being used to Spectrum I needed to set the gyro settings. she is now flying. it was locked in heading lock. I needed to set to rate mode. Thanks again. Gyropilot likes this.

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05-30-2021, 01:35 AM	#3 (permalink)
Cyclone7 Registered Users Join Date: Nov 2017 Location: Lincolnshire, United Kingdom.	I would first check that the correct servo centre pulse width and rudder servo frequency for the servo in question, have been used in the set-up.

05-30-2021, 07:13 AM	#4 (permalink)
Lighthorse Registered Users Thread Starter Join Date: Mar 2020 Location: Addison, ME.	Trying to setup for a friend. SAB 770 Spektrum iX12 AR7200BX (No link cable or box, stock) 1 is 2+ center, 2 is 2+ center, 3 is 3+ center Castle Edge 160 Torq BL9188 Tail servo (pulse 760 Frequency 333) Quantum 4530-500 On spool up, the tail flies to the right, so I changed normal throttle curve to 0-100 and tried to spool up as slow as possible, no luck, barely had time to drop throttle. On the bench the Gyro is reacting the way it should, the tail rotor is spinning the right way. left and right are correct. As for centering the rudder, I can on the bench if I gently ease it over but if I just move the stick it immediately travels hard left or if I try the other direction goes full right. I can't slow the travel down or make it at least respond to stick controls properly. Everything else is working properly and set right.

05-30-2021, 08:45 AM	#5 (permalink)
Morrchew Registered Users Join Date: Jul 2014	Make sure that FBL orientation is correct

05-30-2021, 11:09 AM	#7 (permalink)
Gyropilot Registered Users Join Date: Dec 2014 Location: SE Arizona, USA	That’d be my first guess also… that the center pulse width of the servo isn’t correct. Do you know what version firmware is in the AR7200BX? I believe the last available for that model was 4.0.14. John L.

05-30-2021, 02:55 PM	#9 (permalink)
Gyropilot Registered Users Join Date: Dec 2014 Location: SE Arizona, USA	Glad you figured it out and thank you for posting what you found. It helps all of us learn. John L.

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