Turnigy 9x + FrSky Djt, no servo control

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Turnigy 9x + FrSky Djt, no servo control

Postby moparmuscle1972 » Sat Mar 23, 2013 7:58 pm

i decided to follow the crowd and upgrade my turnigy 9x to the infamous, untouchable Frsky system. However, upon installation and (assumed) successful binding, i have absolutely no servo control at the sticks or switches. Only when the receiver is powered on the servos do their jitter for a moment telling me that they're powered and working, but there's still no control with my inputs and the servos don't hold their position.
If it helps to know, i did the trainer port fix with the resistor on the 9x pcb, then changed it back to a solid wire after i got the frsky module.
also, i'm using the v8frII reciever
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Re: Turnigy 9x + FrSky Djt, no servo control

Postby cynr100 » Sat Mar 23, 2013 11:07 pm

Mopar,
Did your original 9x have a wired module, if so did you do the FrSky conversion http://www.alofthobbies.com/diy-telemetry-module.html to a non-wired module, refer http://www.youtube.com/watch?v=DHnV6hGH108

On the back of the DJT Tx module are 2 switches, for your Rx, switch 1 is down and 2 is up (on).

If all that is okay then the problem may be in your binding.
Tx on whilst holding the bind button, then release, red light should be flashing on the module.
Rx, power up whilst holding down the bind button (3 hands good for this) red light should be flashing, then release.
Power off Rx then Tx.
Power up Tx then Rx, green light should be showing on the Rx.

Only if you have 9x that did not have a wired Tx module or you have completed the DIY module as above will the FrSky work as a plug and play.

Hope there is something in there to assist you.

Cheers Dennis
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Re: Turnigy 9x + FrSky Djt, no servo control

Postby moparmuscle1972 » Sun Mar 24, 2013 5:21 am

thanks for the quick reply =)
this one had the turnigy radio module that came with it and i got the frsky djt for the jr style module. BEFORE switching to frsky, i bound it and hooked it up to my airplane. Everything, all inputs worked. Then did the resistor mod and backlight and ordered the frsky djt module + v8frII. While waiting for that for about 2 months, it sat. in the meantime, i removed the original radio module by desoldering the antenna cable from the turnigy module. After i got the frsky system, i shaved the connector pin shroud down to fit, plugged it in, did an hour of reading trying to figure the correct way to bind ( xD ), finally got a solid green light on the receiver, but no servo response to my input, only that jitter when the rx is powered on.
My brain hurts trying to figure out what could possibly be wrong >.<

Thanks, any information helps
Ty
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Re: Turnigy 9x + FrSky Djt, no servo control

Postby BillGriffiths100 » Sun Mar 24, 2013 9:33 am

Mo,
Have you checked the continuity of the signal trace now that you have removed the resistor?
The fact that the rx and tx modules are binding and the servos are juddering indicates that the link is OK.
Therefore just lack of signal input could account for what's happening.
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Re: Turnigy 9x + FrSky Djt, no servo control

Postby moparmuscle1972 » Sun Mar 24, 2013 4:00 pm

yes, that's what i was thinking to be the problem, i checked it again and there's good continuity all the way between the back module plug pins and the plug on the cable that goes to the motherboard. is there any way to check for actual ppm signal output? is it possible for it to be powered when it's cracked open? (i have a Craftsman digital multimeter)
Ty
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Re: Turnigy 9x + FrSky Djt, no servo control

Postby BillGriffiths100 » Sun Mar 24, 2013 6:15 pm

Yes if you set the meter to AC (smallest voltage) and measure between negative and the signal line you should get a reading on the meter about a volt or so I can't remember offhand.
Also the other thing to check is that the TX output is set to PPM and not PCM.
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Re: Turnigy 9x + FrSky Djt, no servo control

Postby moparmuscle1972 » Sun Mar 24, 2013 7:40 pm

well, i used the 200 vAC selection on the multimeter, didn't get anything. i jumped a wire from the surface ground thing that connects to the prongs when the halves are closed, so there shouldn't have been a problem there. got about 5v dc on the power pin, and 3v dc on something else. There isn't anything between the cpu and the ppm pin, right?
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Re: Turnigy 9x + FrSky Djt, no servo control

Postby BillGriffiths100 » Mon Mar 25, 2013 9:31 am

Looking at the back of the transmitter with the aerial upwards
If you got 3 volts on the top pin that's the pulse train going to the transmitter module.
so that appears present
Next pin down is the -ive and the next the +ive
See Bruces video:
http://www.youtube.com/watch?v=DHnV6hGH108
Do you have the standard software or have you reflashed to the ER9x firmware.
Either has the option to transmit in PPM or PCM mode if your transmitter has become switched to PCM it won't work.
Check the manual for the standard version at:
http://www.google.co.uk/url?sa=t&rct=j& ... 8598,d.d2k
Page 14
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Re: Turnigy 9x + FrSky Djt, no servo control

Postby moparmuscle1972 » Mon Mar 25, 2013 11:15 pm

now i'm not getting anything but a little ( - ) in front of the digits on the multimeter between the middle pin and the second pin, same for middle + fourth pin. Has factory Turnigy firmware set to ppm
i'm afraid i'm running out of area for troubleshooting this problem, it might be out of my hands =(
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Re: Turnigy 9x + FrSky Djt, no servo control

Postby BillGriffiths100 » Tue Mar 26, 2013 8:30 am

To isolate the problem try rewiring the old module aerial and see if it still works with the original setup.
If it does then the new module or RX is faulty.
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