Upgrade Futaba T6EXA with Frsky DHT module

[Dave Hess]

Despite watching about 20 Youtube videos and trawling loads of forum posts, I can't figure out how to wire in the module. I know in principle what I have to do, but I don't know which wires should are which and what they should be connected to.

The wires on the RF original module are:

Grey: OUT

Orange: IN

Purple: VCC

Bkack GND

White: ANT

Black: GND

White: MOD

Red: VCC

The Frsky module from Hobbyking has three flying leads: Black, yellow and red, plus an edge connector marked: Gnd, 5v, Txd, Rxd. Nobody mentioned what that edge connector is for. Is it for programming somehow or firmware upgrade? No mention if it in the instructions.

Is MOD the same as PPM?

[PatMc]

The edge connector is for firmware upgrades as well as the now discontinued FLD-02 telemetry display.

This RCG thread might help identify the T6XE rf connections.

This thread in this forum seems to confirm that MOD is the PPM connection.

Edited By PatMc on 24/08/2018 00:21:51

[Dave Hess]

Thanks for that. i have some progress now. Let's assume MOD=PPM. That's still not certain though because the guy didn't confirm that it worked, and somebody else said he was going to use IN, but he didn't confirm either. Ground and VCC (battery) are easy, so I have a way to try to wire it.

I'd like to leave the 35mhz board in place and be able to switch between the two. Can I put a SPDT switch on the battery wire to each module so that only one is powered at a time? I see other people do it in more complicated ways using DPDT switches. is that necessary. Obviously, the less switch points there are, the more likely a connection will fail.

Edited By Dave Hess on 24/08/2018 10:17:05

[Dave Hess]

I think I have it figured: IN, OUT purple VCC and GND next to it all go directly to the buddy box connector, so OUT is also PPM. The VCC there is about 0.7V lower, maybe because there's a diode in line to protect it from the buddy's transmitter., The other VCC and MOD are therefore the battery and PPM for the RF board in this transmitter.

That leads me to the question: Who's rf board is used when buddy boxing? I guess that it's the slave's, but why do you need VCC on the connector? Is it to power the slave's RF board too? We have battery in on pin 5 and out on pin 6. It must be these pins used to switch between master and slave somehow because there are no others AFAICS.

One of the pins on the buddy box connector must be able to disable the RF board when controlled by buddy's transmitter. maybe I could use that function to switch between modules. I need to investigate further.

Edited By Dave Hess on 24/08/2018 13:52:01

[Dave Hess]

I don't seem to get any luck. I have three transmitters and four receivers, but still don't have a combination that works. No range on my Spektrum, My Frysky X7S won't bind with the V8R4-II receiver. It binds with the S6R, but I don't have the dongle to setup the receiver.

Now I converted my Futaba T6EXA to work with the V8R4-II receiver and every channel works except ailerons and rudder are reversed. The computer now seems to be disabled so I can't get at any of the model settings. I completely removed the old RF board. Do you think there's something in it that links to the computer?The LCD screen is still working and showing the voltage and model 1, but all the buttons are disabled, so I can't change anything.

The wires that remain disconnected are VCC, GND, IN and OUT, which all seemed to go to the trainer connector.

[Dave Hess]

OK, Panic over. I forgot that you had to press both mode and select buttons to activate the settings. It's a while since I've used it. Everything's working now. Success at last. Now I can go flying. Yippee, I have a nice Thunder 180 to try out as well as my Wat4 Foam E.

[jeffrey cottrell]

Hi Dave

Glad to hear you got it working. I have converted a couple of JR transmitters using the same module and they work fine.
One thing though, that caught me out, and you may not be aware.
The module as supplied has a three way switch marked 1-way, 2-way (telemetry) and FW for firmware update.
I was unlikey to update the firmware, and don't use telemetry, so I just unplugged this switch and left it off.
Worked fine except on rare occasions I would get a mysterious signal loss leading to failsafe (helicopters) which only lasted for a fraction of a second.
Tore my hair out on this one, but eventually got a clue from the guy who has taken over JR servicing from MacGregor.
He pointed out that leaving this switch off put the module in permanent 2-way mode. He suggested that the proper way to do it was a solder bridge across the two switch contacts which left it in permanent 1-way mode.
Quite how this caused the power out I don't know, but the proof was when I had to re-bind my receivers once I had done this operation.
Had no issues since.
The pins to short are the centre and the outer one nearest the edge of the board.

Hope this helps

Jeff

[Dave Hess]

Yes, that's a neater way to do it and eliminates the possibility of the switch getting set to the wrong position. If I do another one, I'll probably do it like that. When I did mine, I wasn't sure which position the switch was supposed to be in, so thought it was easier to find out by trial and error. Where were you when I needed you? Thanks anyway.

[PatMc]

Hi Dave, pleased to see you you're now have your V8R4-II receiver up & running.
Just a little puzzled that you took the route you did.

Have you made any progress with the Taranis ?
Downloaded Opentx Companion &/or any documentation for instance ?

Edited By PatMc on 25/08/2018 21:04:04

[PatMc]

Posted by jeffrey cottrell on 25/08/2018 17:38:30:

One thing though, that caught me out, and you may not be aware.
The module as supplied has a three way switch marked 1-way, 2-way (telemetry) and FW for firmware update.
I was unlikey to update the firmware, and don't use telemetry, so I just unplugged this switch and left it off.
Worked fine except on rare occasions I would get a mysterious signal loss leading to failsafe (helicopters) which only lasted for a fraction of a second.
Tore my hair out on this one, but eventually got a clue from the guy who has taken over JR servicing from MacGregor.
He pointed out that leaving this switch off put the module in permanent 2-way mode. He suggested that the proper way to do it was a solder bridge across the two switch contacts which left it in permanent 1-way mode.
Quite how this caused the power out I don't know, but the proof was when I had to re-bind my receivers once I had done this operation.
Had no issues since.
The pins to short are the centre and the outer one nearest the edge of the board.

Hi Jeff, I fail to see how leaving the module in 2-way mode (AKA D8 mode) isn't the "proper way" or how it will have any ill effect on V8 series II rx's. OTOH leaving the module on permanent 1-way (V8 mode) will remove the benefits of telemetry range & low voltage warnings when using D series Rx's, it will also remove the audible range check reminder for both V8 & D series Rx's.

I've been using an MPX Cockpit SX with an original version DHT module since before the first version Taranis X9D was launched. The module has always been set to D8 mode, for at first, D series Rx's then when V8 - II Rx's came out several of these.
Earlier this year I migrated most models with D & V8-II Rx's over to my Taranis XD9 where they are used in D8 mode.
I've had no glitching or rf problems with any models varying between a zippy little 28" X-Kraft (V8R4-II) to a 2.4mtr E- glider (D4R-II) that's often flown to the limit of my visibility.

 

 

Edited By PatMc on 25/08/2018 21:50:19

[jeffrey cottrell]

Hi Pat

Honestly, neither can I. All I know is that I was chasing my tail for ages trying to pin down the problem. Eventually got to talk with Mike Ridley, who handles repairs and servicing for JR equipment.

He has done the self same conversion many times on customers gear, and always did it this way. Never had an issue.

More from desperation than anything else I gave it a try and it worked.

Never really felt the need for telemetry and given this was with JR 2610 and 2720 transmitters, which have no way of displaying readings anyway, didn't see it as much of a loss.

Proof of the pudding ............

Jeff

[PatMc]

Hi Jeff,

I've never owned or used a FLD-02 display unit, the telemetry range & voltage limit warnings are audible for the D series Rx's only. Particularly useful when flying any model relying on a Rx battery & thermal gliders where there might be limit of range concerns.
The audible range check is of course a reminder for both types of Rx but only when the module is set to D8 mode.
I know of a couple of people who had the original V8 modules that did range checks using the output limiting facility then forgot to switch back before taking off because they didn't notice the LED only indication - a green instead of red + green LED

I think my pudding must be a different type from yours.

[Dave Hess]

Posted by PatMc on 25/08/2018 21:00:43:

Have you made any progress with the Taranis ?
Downloaded Opentx Companion &/or any documentation for instance ?

Yes and no. After many more hours, I've got most of the Taranis figured out as far as basic things are concerned. With LBT OpenTX software, which is standard in the X7S, that V8R4-II receiver is not compatible. I have the S6R receiver that is bound and responding, but I can't use it until I get the dongle to set it up properly because the stability part of it needs to be initialised and setup. At the moment, it goes nuts whenever it's moved. I think that part can be disabled by assigning a switch, but it will be easier to setup with the dongle and PC.

I've put the Spektrum aside because clearly there's something wrong with it. Maybe a new receiver will sort it out, but I'm fed up spending money on things that don't work. It could be the transmitter that's faulty, so I need to find someone else with a Spektrum to swap parts to see what doesn't work. I have one transmitter and receiver that's working now and the Traranis will be working as soon as my dongle arrives, so I don't really need the Spektrum now.

Edited By Dave Hess on 25/08/2018 23:52:48