Frsky DH8 module install problem

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Frsky DH8 module install problem

Postby graenet » Sat Feb 11, 2012 2:58 am

I installed a new DH8 telemetry module into a new Turnixy 9X following rcmodelreviews youtube tutorial which shows installation of the non-telemetry module. AFAICT the differences are marginal; you just need to locate the three-way switch somewhere and the soldering is the same.

The unit powers up and I was able to bind one of my D8RSP receivers, however in normal mode the LED flashes green/red *very* rapidly (far more frequently than in bind mode). The RX does hook up (red light on RX stays solid) and some input is possible, however for the most part the servos jitter wildly and begin to overheat.

It seems that the TX is pulsing output signals. I tested the three way switch (for 1way, 2way, firmware) but its ok - and then tried removing its harness completely, which leaves the module in 2way mode, but so far nothing alters this malfunction. I'm certain the bind switch is not sticking and has room to move freely as it functions to put the module into bind mode when used.

You can see a short video of the phenomenon here:

I took lots of care with my soldering and handling but it looks like this is a dud module that I'll need to return. However it is the first time I've tried this module install, so maybe I'm missing something obvious. Any feedback much appreciated.
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Re: Frsky DH8 module install problem

Postby Keith » Sat Feb 11, 2012 9:54 am

The pulsing red light is normal... Will it go into range test mode, solid green light...?
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Re: Frsky DH8 module install problem

Postby ergocentric » Sat Feb 11, 2012 7:58 pm

Not sure about the Turnigy tx, but I had my Futaba switched to PCM mode when I first tried it after conversion, but it must be in PPM mode.
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Re: Frsky DH8 module install problem

Postby phil f » Tue Feb 14, 2012 11:51 am

I had the same thing as ergocentric with the last Tx I converted . Switched it back to PPM and all worked OK .Worth checking before going any further.
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Re: Frsky DH8 module install problem

Postby kaptain_zero » Tue Feb 14, 2012 11:17 pm

Just for clarification, it sounds like you are trying to use one way mode with a 2 way receiver? One way mode is for use with the V8 series receivers. Two way mode is for use with the "D" series receivers and the two are not interchangeable afaik.


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Re: Frsky DH8 module install problem

Postby graenet » Fri Feb 17, 2012 10:01 pm

Thanks to all who posted. I think I've sorted out the problem:
- the rapid flashing seems to be normal (confirmed by two other posters ta)
- I tried using different servos when rcmodelreviews suggested the hxt900's do not like high frame rates and the problem is not apparent with a different brand of servos (I used hk 9gm analogs)
- conclusion; my module is installed and working ok, just have to figure out how to drop framerate in order to use HXT900s or just not use low rate servos.

Thanks again everyone.
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