Trainer cable wiring

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ShowMaster
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Trainer cable wiring

Post by ShowMaster » Wed Mar 13, 2013 6:48 am

I'll start thus by asking if anyone has the wiring diagram for making a trainer cable for older Futaba 7ch TXs? They use the large 6 pin din connector. The master tx powers the trainer tx and it also kills the rf out on the trainer.
I've found some info on line but I'm not clear if both ends of the cable connector is wired the same?
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SM


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Kilrah
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Re: Trainer cable wiring

Post by Kilrah » Wed Mar 13, 2013 12:10 pm


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ShowMaster
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Re: Trainer cable wiring

Post by ShowMaster » Wed Mar 13, 2013 3:24 pm

Thanks Kilrah,
Not being a Futaba person I never owned any to buddy together.
Form your link and what I could find on the subject, it looks like I just wire both ends to the posted pinout.
The tx power switch must control what tx sends power and ppm in, and what tx receives the power, ppm out, and powers down the RF out stage.
Master tx power switch on...
Sends power to the trainer along with receiving the ppm from the trainer.
Trainer tx power switch off...
Receives power from the master.
Send out the trainer ppm.
Kills the trainer RF out stage or module power.
Both Futaba's are computer radios and take modules. I've installed a Frsky module in the higher end tx as the master. They were donated and I hope to teach with them. They both need some toggle switch replacements and I'll do that as I find old TXs being sold for parts at club events.
I could use my 9x conversions but this setup may be left in storage at our field for others to use. The TXs were free and the Frsky module form Aloft was $30 to my door and I have many older Frdky 2 way RXs I can donate to the cause.
I hate to see TXs get scrapped especially a computer type. Win win if it works out.
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gohsthb
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Re: Trainer cable wiring

Post by gohsthb » Wed Mar 13, 2013 5:30 pm

I have a round to round Futaba cable at home. I can see where the wires connect from end to end if that helps you.
-Gohst

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Kilrah
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Re: Trainer cable wiring

Post by Kilrah » Wed Mar 13, 2013 5:51 pm

ShowMaster wrote:Form your link and what I could find on the subject, it looks like I just wire both ends to the posted pinout.
Not exactly, obviously the PPM out of the slave needs to go to PPM in of the master.

Normally a genuine cable has one Master end and one Slave end. Only the PPM out of the slave is connected to the PPM in of the master, no "return". You obviously have ground, a power line so that the master powers the slave, and a bridge in the slave plug to disable RF.

BUT... there have been many variations of the system, so I'd recommend NOT playing with the power. Some radios have been known to smoke... remember this connector dates back from a time where manufacturers expected you to buy 2 identical radios to train someone...

So what I was doing was not to put any power wire, and always power each radio from its own battery. Also, as the bridge thing doesn't seem to work the same way on all models I'd avoid that and just remove the crystal or module on the slave TX. So just a 3-wire cable, with common ground, and crossed out/in and in/out. That way no risk and no need to check which way you plug the cable.

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