GT3B Hack Question and Answer Thread

[mikemcE]

That’s working as intended. Yes it can work with multiple receivers, But it only is a single transmitter.

If I remember, some dual stick are setup for that, on RC tanks and construction equipment . Big $$$$


Hang up and Drive

[bugman72]

Yes, JoJo513, that, unfortunately, is the nature of the radio. It will bind to multiple receivers, but when switching models it does not kill control of the previous model's receiver. The bind is not a 100% unique handshake between the radio and receiver.

So, unless you actually disconnect the battery or switch the other vehicle off, you will not be able to control the vehicles individually on the fly.

[big specht]

I’ve been looking at these radios for a 4ws radio and light control. Is there a way to add self centering toggle switch to use for the rear steer switch ?

[blackdog360]

Is there any way to get expo to work on channel 3 for dual esc?

[charlieboyd65]

I hacked my GT3C recently and love it with my dual ESC (HH BR Minis) MOA crawler. I also have rear steer. I currently have it setup to run momentary F/R dig off of the DR button and the rear servo off the CH3 button setup as incremental movement (and plugged into Ch3 on the receiver. My rear ESC is plugged into Ch4 on the receiver. I'm trying to do two things unsuccessfully though.

1. Program the C button on the grip to return the rear steer back to center immediately. Edit Just figured this one out, but every time I turn the transmitter on or exit the REV menu the rear wheels shoot all the way left. No big deal because Incan click the C button and return it to center, but that seems odd.

2. Setup the ST buttons to toggle 4WS, crabwalk, and back to front steer. When I try to use the 4WS function it looks like it references CH4, which is my rear ESC, not my rear servo. Do I have to use CH4 on the receiver to use the 4WS function, or can I change that to CH3 somehow?

Thanks in advance.

[GTSLOW]

Does anyone know if it would be possible to reprogram "CH3 TRIM" or "-DR+" to run a vanquish dig? What I'm hoping to accomplish:

Switch center position (servo is all the way forward) normal operation 4WD

Switch forward position (servo is centered) unlocked rear wheels - powered front wheels

Switch rear position (servo is all the way back) locked rear wheels - powered front wheels

My firmware is 061 according to the global menu.


EDIT*

For some reason when cycling through the type of channel I want there is no MP1, MR1, MP2, MR2, etc... What on earth?

[losikid]

Originally Posted by GTSLOW

Does anyone know if it would be possible to reprogram "CH3 TRIM" or "-DR+" to run a vanquish dig? What I'm hoping to accomplish:

Switch center position (servo is all the way forward) normal operation 4WD

Switch forward position (servo is centered) unlocked rear wheels - powered front wheels

Switch rear position (servo is all the way back) locked rear wheels - powered front wheels

My firmware is 061 according to the global menu.


EDIT*

For some reason when cycling through the type of channel I want there is no MP1, MR1, MP2, MR2, etc... What on earth?

Yeah, you can use the Multi-Position Functionality.

My memory is abit rusty, but try this

Setup Multi-Position:
Scroll to End Point, press and hold enter
Scroll to P1, press enter
Scroll to desired channel (3 for example), press enter
Scroll To +100, press enter
Scroll to 0, press enter
Scroll to -100, press enter
Scroll to END, press enter
Press back/end afew times

Now assign a switch
Scroll to Reverse, Press and hold enter
Scroll to 3 for Ch.3 Trim, press enter
Scroll to MP1, press enter
Scroll to BRS so it will reset to default if you long press, press enter
Scroll to RE0, press enter (fyi RE1 will reverse the switch)
Scroll to PV0, press enter
Scroll to RO1 so the multi-positions are sent in a loop

Now ch3 trim should control it. It should default to 4WD.

The forward/back clicks of the switch will loop through the 3 postions. If you long press forward or back, it will return to 4WD.

MAKE SURE TO SET YOUR ENDPOINTS TO ZERO before plugging in your dig servo and slowly increment the end point until the dig is fully actuated. Usually there is an audible noise when the servo binds up, back off a couple clicks from the bind point.

[GTSLOW]

Originally Posted by losikid

Yeah, you can use the Multi-Position Functionality.

My memory is abit rusty, but try this

Setup Multi-Position:
Scroll to End Point, press and hold enter
Scroll to P1, press enter
Scroll to desired channel (3 for example), press enter
Scroll To +100, press enter
Scroll to 0, press enter
Scroll to -100, press enter
Scroll to END, press enter
Press back/end afew times

Now assign a switch
Scroll to Reverse, Press and hold enter
Scroll to 3 for Ch.3 Trim, press enter
Scroll to MP1, press enter
Scroll to BRS so it will reset to default if you long press, press enter
Scroll to RE0, press enter (fyi RE1 will reverse the switch)
Scroll to PV0, press enter
Scroll to RO1 so the multi-positions are sent in a loop

Now ch3 trim should control it. It should default to 4WD.

The forward/back clicks of the switch will loop through the 3 postions. If you long press forward or back, it will return to 4WD.

MAKE SURE TO SET YOUR ENDPOINTS TO ZERO before plugging in your dig servo and slowly increment the end point until the dig is fully actuated. Usually there is an audible noise when the servo binds up, back off a couple clicks from the bind point.

THANK YOU!

Follow up question, I recently hacked another GT3C. Upon initial startup I apparently hadn't fully depressed the power button. So the CAL screen popped up and the radio shut off. Is there a way to re-calibrate everything?

[losikid]

Originally Posted by GTSLOW

THANK YOU!

Follow up question, I recently hacked another GT3C. Upon initial startup I apparently hadn't fully depressed the power button. So the CAL screen popped up and the radio shut off. Is there a way to re-calibrate everything?

Turn the wheel all the way to the right, then press and hold enter

Calibrate menu:
===============
- enter it by wheel right-turn and ENTER-long
- 6 menu items starts to blink (+ 2 arrows if CH3 is potentiometer)
- use END or ROTATE to change channels
- there is also channel 3 representing CH3 button (for those who will do
    some 3-position switch/potentiometer modification)
    > There is 1K resistor connected between CH3 button and +5V, so
      simply connecting linear potentiometer instead of CH3 button
      will not work. Usefull results can be done with logarithmic
      potentiometer 10K which has 1K at half of turn. Or eliminate
      internal resistor to +5V, connect potentiometer between +5V
      and GND and potentiometer output instead of CH3 button.
- there is also channal 4 representing battery voltage
- calibrate as usual (for channel 1/2 left+mid+right and ENTER)
    > calibrated value will disappear from menu
    > it is not needed to calibrate all values
- calibrate CH3 potentiometer (if selected at global config)
    > only left + right positions
- calibrate battery (it will not be probably needed to use this)
    > select channel 4
    > press ENTER
    > set your current battery voltage (measure it by voltmeter)
    > press ENTER to save it or END to no-save
- press BACK-long or ENTER-long to end calibrate menu and save values

[GTSLOW]

So I have channel 3 assigned to the "CH3 Trim" switch and it works GREAT for my servo winch. I'm trying to do the same with the -D/R+ switch. I'd like that to be channel 4. However, when I go to the button assignment menu I select "d" which is for the -D/R+ switch and it only gives me these options "CH3, EXB, EXF, EXS, DRB, DRF, DRS, TR2, OFF, MP1, DIG, 4WS, CS3, CS2, SSR, SST, ST3, ST2, ST1". There is no option for any of the other channels. I have set my channels to 6 on the main menu.

**

Edit. So I can't seem to get access to anything beyond channel 3. I've gone to the home menu where it shows F 062, scroll to c, and I've tried setting it to 4, 5, 6, 7, 8 channels and I still can't assign anything beyond channel 3.

[Raulez88]

Try on NAME, Enter-long. Here you can change the number of channels for that model

[cloudswimmer]

Anyone know if RC Addict is still in business? I want to buy his hacked GT3C .. and he shows it on the site .. but you know how it is with business and peoples lives these days with the pandemic, personal issues, etc. He has no email and hasn’t responded to my messenger message. Thanks

[soopahfly]

Has anyone had any success flashing the gt3c with this style programmer? I noticed that some of the pinout are different to what's on the guides.
I getting a constant beeping as soon as I ug the radio in.

Sent from my Pixel 5 using Tapatalk

[mikemcE]

That’s what I used. Follow setup precisely, all the proper pins seem to be there.


Hang up and Drive

[cartronicshn]

Hey guys a little help if possible, since i cant seem to find receivers for the 7 ch radio i bought of banggood and still have a couple of hacked gt3b left, i am now looking for the 8 ch receiver that binds to this radio, cant recall what model it was..

[mikemcE]

https://hobbymatehobby.com/products/...yABEgIFHvD_BwE

I’ve only used the 3and 6


Hang up and Drive

[QuesoDelDiablo]

Originally Posted by cartronicshn

Hey guys a little help if possible, since i cant seem to find receivers for the 7 ch radio i bought of banggood and still have a couple of hacked gt3b left, i am now looking for the 8 ch receiver that binds to this radio, cant recall what model it was..

Ive got a flysky compatibility chart somewhere, I'll try and find it for you.


*Edit

Looks like R9B is the Rx you want for 8ch into a GT3B or GT3C Tx

[cartronicshn]

Thx queso and mike for the help.

[Oldmanbluntz]

Just curious if anyone could help me out with adding the potentiometer for the ch3 button.

I know how to wire a pot, I just can't seem to figure this one out, and where on the controller to hook the 3 wires to. Where do I get the 5v from? Is resistor labelled r18 the one you eliminate? The line with resistor r18 that leads to the ch3 button, then to ground, I assume is the channel 3 feed from the microcontroller? I would hook the middle leg of the pot to that line where the resistor is eliminated?

Sorry for all the questions, I just can't seem to find the information on how to do this anywhere. Thanks for any help you can give me.

[Oldmanbluntz]

Never mind. I got it figured out. I looked up the datasheet and pinout for the Stm8 chip on it, and started probing with my multimeter. I didn't realize that the other side of r18 that went to the button also went to pin 19 on the Stm8. So positive lead of pot to, according to the orientation of the screenprinting, the bottom side of resistor r18, the signal middle lead of the pot to the top side of r18, and the other side to ground.

I made the mistake of figuring the housing for the micro USB port on it was a proper ground. It was not apparently, which is what was causing my issue.