Supplement for the transmitter Futaba-F14? - Need help with this supplement.

[DrainZero]

Hi modelflyers,
I'm using a futaba f-14 for flying and want to use it also for fms. This should be possible. There is an supplement in the manual for the Futaba-F14. The picture that explains it all is a little out dated cuz futaba changed the board but i found the trainer plug. My problem is that i don't know where to connect the outcoming leads with the 25 pin Sub-D. The U1 is as near to lead 5 as it is to 1, so i also have to guess what the u1 is. (by the way, is U1 the same as ground?). So i need a little bit explaining by the picture. Can anyone help me with this?

Greetz, Joost
???

[Mike Roberts]

Joost

In what way has the PCB changed? You can check which pin is ground and which is positive by checking continuity with teh battery. Hopefully the signal pin then becomes obvious.

It might also be simpler to use a serial IRQ interface. Follow the standard circuit diagram on my website but swap R1 and R2 to cope with the smaller signal magnitude.

Cheers

Mike

[DrainZero]

Hey mike,
I'm gonna build the serial IRQ interface from your website. You mentioned that R1 and R2 should be swapped and Tx power is only for the Micron R/C. I changed the diagram and placed it . Can you check it for me?

Together with the diagram i placed two pics. One of my Tx pcb board and one of what should be ppm-signal in an Oscilloscope. website explained how you can check the ppm-signal with an oscilloscope program. Can i be sure that this is the signal? If so the upper pin of the train port is ground and the second is signal.

Greetz, Joost

[Mike Roberts]

I believe you have it correct. The pins you note are the same relative to the socket as in the FMS manual. The signal looks a little noisy but is probably right. You have 9 pulses which is right for 8 channels plus synchronisation pulse (the long gap). Check the time difference between the successive rising edges. Should be 1 -2 ms. The first 4 gaps should lengthen and shorten as you move your sticks (one for each axis.

Yes your revision of my diagram is coorrect. I have wondered about doing this any way as the micron option is no longer available.

Please come back if you have any further questions.

When you have it working can I use your photograph on my website?

Cheers

Mike

[DrainZero]

I tested the signal with the oscilloscope program and moved the stick's. It's great to see how the signal changes with the stick's position . I'm now gonna build the diagram. Let's pray it will work .

It's no problem to use the photograph on your website mike. If you want the non-resised and unchanged photograph you can mail me: j_asten@hotmail.com.

greetz, Joost

[DrainZero]

it isn't working ,
I tried it on two different computers. I downloaded fms 6 to see if there was a signal, but there wasn't any. I tried to reverse ground and signal (also in the oscilloscope program) but it gives a positive ppm and futaba has a negative ppm. it produces a voltage of 0,65V, is that ok? I don't know what i can do to make it work . Has anyone some advice?

greetz, Joost

[Mike Roberts]

Joost

Check you have the correct ground connection. Should be zero resistance to your battery negative. The signal should all be positive. Negative is not possible. You can be moving botyhe sides of zero volts (max approx 0.65v set by TR1) if the signal is coupled via a capacitor. This is the case for JR sets and hence the different input circuit (see my website). This might be worth a try.

Cheers

Mike

[DrainZero]

Thanks , it's working now. I had the wrong pin for ground as you suggested i checked if there was zero resistance to the negative pole of the battery. Not the first but the fourth pin is ground. Thanks again.

Greetz, Joost

[Mike Roberts]

Joost

Great. Please confirm the connections on your photograph and email me the original and I will put it on my website.

Thanks

Mike