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Strange behavior of GY 401

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Strange behavior of GY 401

Old 10-26-2002, 07:13 AM
  #1  
tindra
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Default Strange behavior of GY 401

I have a brandnew Hitec Eclipse 7 and a Futaba GY 401 gyro. First I switch on the Tx and after that the reciever. The servo connected to the gyro swings fully 90 degrees from the centerposition and after a few seconds back to center again. This means that I canīt have the linkage for the tailrotor connected during startup. Iīm starting the radio in Head holding mode. I know that the gyro takes a few seconds to center but this behavior will destroy my tailrotor. Any ideas?
Peter
Old 10-26-2002, 10:15 AM
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z11355
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Default Strange behavior of GY 401

What servo are you using w/ the 401?
Old 10-26-2002, 11:11 AM
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tindra
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Default Strange behavior of GY 401

Iīm using a non digital servo. JR NES-810G. The dipswitch on the gyro is set for a non digital servo. Except from this 90 degree thing the gyro seems to be working fine. I havnīt flown the chopper yet so I donīt know how the gyro works during flight conditions. If i connect the servo directly to the reciever and switch on the power, the servo doesnīt move. So the problem must be in the gyro somehow.
Old 10-26-2002, 11:58 AM
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z11355
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Default Strange behavior of GY 401

This behavior was first seen as I recall on the
Futaba GY501. During the gyro power-up
and initialization, it (the gyro) outputs a signal
that JR servos interpret as beyond max
deflection resulting in what you see (servo
goes hard over to one side). On the 501,2 and
601, you can start up the gyro in non-HH which
prevents that but on the 401, you have to
start it up in HH so it can read 'center'.

Someone in Germany (I think) designed a
small circuit to get past the problem but I think
that most people simply use the Futaba 9253
servo which is really optimal for that gyro.
Old 10-26-2002, 01:13 PM
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Whoison2nd
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Default Strange behavior of GY 401

I'm using the JR DS8417 servo with my Fut. GY401 Haven't flown it yet.. but everything seems to be working fine with that set up..
Clay
Old 10-26-2002, 02:20 PM
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tindra
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Default Strange behavior of GY 401

z11355!
Thankīs for the information. Your comment makes sense to me. What if I put a standard on/off switch between the gyro and the servo? In this way I can have the servo disconnected during initialization. Must the servo be connected during initialization?
Old 10-26-2002, 02:35 PM
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crash1953
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Default Strange behavior of GY 401

This might sound a little dumb ,but are you turning the transmitter on first?You are suposed to have the transmitter on when you turn the heli on. I have several Futaba 401 gyros and I have never seen that happen yet ..Also I always start mine without the HH locked in .
Old 10-26-2002, 04:02 PM
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tindra
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Default Strange behavior of GY 401

I am starting the radio first and second the heli. I have tried starting with and without HH locked in.
Old 10-26-2002, 04:13 PM
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crash1953
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Default Strange behavior of GY 401

Have you tried any other tail servos? I just went tomy shop and tried 5 ifferent servos with the 401 and all of them worked fine .. including a JR 537 standard servo .. I tried futaba 3003 ,JR537 Futaba9202, Fubaba s148 Airtronicssomething or other number and they all worked good .. Oh I also have used the Futaba9253 with it
Old 10-26-2002, 04:29 PM
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tindra
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Default Strange behavior of GY 401

Crash1953!
Thankīs for your assistance and ideas!
I will try other servos tomorrow since it is getting late in Sweden now. If other servos are fine then itīs probably a servo problem.
Old 10-26-2002, 04:50 PM
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tindra
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Default Strange behavior of GY 401

I got curios so a picked up the heli from the garage and connected my throttle servo to the gyro. Itīs a JR NES591. It swung out a few degrees and then centered as it is supposed to do. I believe that the JR 810 servo is faulty. I will send it back and have it replaced.
Old 10-26-2002, 05:39 PM
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crash1953
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Default Strange behavior of GY 401

I am glad you got it to work ..Youi gave me some ideas too .. I will watch for that in the future ..
Old 10-27-2002, 06:29 AM
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helitroll
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Default Heading hold.

Another thing to check is to make sure all subtrims and trims are centered and you have no REVO engaged. Do not move the heli when you throw the on/off switch. I would not put a switch between the gyro and the receiver. Flying without the gyro is more than interesting.
Old 10-27-2002, 01:57 PM
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tindra
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Default Strange behavior of GY 401

helitroll!
Everything is set as you are suggesting. I was not gonna fly with the gyro disconnected. Only disconnected during initialization of gyro. I agree, flying without the gyro must be very interesting!!

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