FrSky two way and Futaba 8U problem

[peso]

I have installed a FrSky two way transmission module in a Futaba 8U system but can´t get it to work. After binding the servos move erratically. Almost no correlation between the servo and the stick. Receiver seems to bind as the red LED on the receiver is ON after binding. The transmitter works fine with Assan and 35MHz modules so it should be OK. Has there been any compatibility problems between FrSky and the Futaba 8U transmitter?
The receiver is V2. The transmisson module has no version on it. I have read about problems with the connectors but they seem to align well. I am running out of ideas. Maybe I have to return it.

[pushinoldrc]

Make sure your transmitter is set to PPM mode. This can be selected in the PARA (parameters) screen. It should also indicate PPM or PCM on the main screen when you power it up.
Bryan

[RCModelReviews]

I understand that there has been at least one instance reported of a V1 module and V2 receiver being shipped together.

It's easy to upgrade the module if you need to -- the files and instructions are on the FrSky website and you use the cable that came with the module (if your PC has a true serial connector).

[peso]

Looking closer at the module I find that it is marked V2. Of course it could still be the wrong program in it and I will look at the posibility of reprograming it. I have also connected a scope to the receiver and there are pulses but with a lot of jitter. And no pulses when transsmitter is off so there is some kind of transmission. If it was not for the reason that the transmitter works with other modules I would think it was faulty. By the way it is in the PPM mode. I would like to verify that the module really receives a proper PPM pulse when installed but don´t know how to do it without voiding the warranty.

[RobC]

I've been using FrSky with an FF8 for most of the last year, both one way and telemetry modules, and they work faultlessly. I'd suggest you probably have a duff module if the two switches on the module are set correctly. It's possible a switch has been moved to the one way compatibility position, but faulty modules are not exactly unusual.

[RCModelReviews]

Since it's a V2, make sure you've got the right frame-rate selected. The V2 can run with a high-framerate (only for use with digital servos) or a lower frame-rate (for standard servos). Check the instructions (on the FrSky website if you don't have any with the product) and check that you're not using the high-frame-rate mode with standard servos or vice-versa.

[peso]

An instruction was included with the product but I can´t find that two framerates are mentioned. Maybe it was an old version. Unfortunately changing framerate did not help. I have also tried standard and digital servos.

[peso]

I give it a new change and order a new set from HC. Hopefully the new set will work. Then I can find out whether it is the module or the receiver that is wrong and return the wrong part. Or perhaps open it which can also be interesting.
This did not start as I hoped for. It has not so much with cost to do. It has more with confidence. I have flown with Spektrum for a long time but after one crash I do not fully thrust it. I have used Assan also for a long time in smaller planes and never had an issue. But it has only one channel so I don´t thrust it either for bigger gas planes. Now I hoped for FrSky but I don´t know. I like the older Futaba transmitter more than the new ones and hope to be able to convert them.
As an electrical engineer I am surprised how difficult it has been for the industry to change to 2,4. Look back and find that they all have had quality problems. The relaibilty was much better during the 35MHz period. Maybe be they had fired all reseach and development people as they had not been needed for several years.

[RobC]

or possibly because they used more leaded solder!

[peso]

You are right I did not think about that.