GT3B Hack Question and Answer Thread

[losikid]

I'm having an issue I hope someone can help me with.

Been using 2 hacked GT3B's for a couple years now. SCX10 and a TF2 both using 6 channels with a R6B receivers. I didn't like the big thing on the end of the antennas, so a desoldered them, and have never had a problem with these models. Range is still farther than I can see them, so way overkill for a crawler I'm usually right above.

I'm just finishing up a new rig, using 5 channels on an R6B receiver with one of my GT3B's and got it all programmed up and working great. Went out for a test drive, and I only get about 15' of range, and occasionally less than that. I have an external BEC powering servos, ESC is powering receiver.

First suspect was ESC BEC, so I tried it out using an external receiver pack, no change.

I thought maybe the radio was bad, so I tried it on the model it's been paired with for a 1.5 years and I get tons of range still. R6B receiver.

I concluded that maybe removing that little brass tube on the end of the antenna could have caused this issue. So I resoldered it back on, no change. I then thought that the antenna of the receiver must have broken off the board. Checked continuity with my DMM and everything checked out fine there.

So, I bound an 8 channel receiver to the radio, same exact issue, the brass tube removed from this one too. I then bound a 3 channel receiver I had to the radio, no issues with this one, full range.

I'm not sure what to try next. I know the radio works fine, because it works on an old R6B, and works with a new 3 channel Rx. (I even tore apart the radio to check its antenna connection. Everything is solid).

I can't see how I would have received a defective R6B and R9B from different sellers. I don't think removing the brass tube on the end of the antenna is causing the issue because both my working R6B's have it removed (along with 3 others I've setup for friends), and I've reattached it without a change.

I have also put conformal coating on all the receivers, all in the same batch. Physical examination shows nothing out of the ordinary.

Any thoughts?

I have a new R6B on the way to try that out. Wasn't sure what else I could do.

What happens when you put your old R6B in the new rig?

 

[Brainanator]

What happens when you put your old R6B in the new rig?

I did not try that, will try it out tomorrow when I get back to tinkering. I don't think it will make a difference though since I also tried both bad R6B and R9B on the bench with a just a receiver pack and spare servo. Just to rule out some kind of weird interference with the new rig.

 

[Brainanator]

Well I tried an old working R6B in the rig and range tested out fine. Got my new R6B in today and range tested out fine with the brass tube on the antenna still. I have plenty of room in this Rx box so I'll leave this one attached for now.

I can't believe I got faulty R6B and R9B from different sellers, I must have messed something up when I put conformal coating on them. So I put conformal coating on the new one. Still works fine.

I did notice the new R6B is version 17, while the bad one is version 16. But my two good, working R6B's are also V16. Maybe coincidence.

Attaching a pic below. Rx on the bottom has very poor range, Rx on top works just fine. Both have conformal coating when the pic was taken.

 

[losikid]

You might of shorted out the antenna when you snipped it. Since they are a coaxial wire.

 

[Brainanator]

You might of shorted out the antenna when you snipped it. Since they are a coaxial wire.

I didn't snip the antenna, I have always removed the brass tube by de-soldering it. Also while I was checking continuity of the antenna with the board I checked for a short and came up clean.

 

[ToSte]

I'm building a vehicle that will have the doors open and shut via my hacked GT3B and a 6 channel receiver with individual servos on channels 3 and 4.
Is there a way to program these as one touch rather than having to hold the button down? Meaning one click fully opens one door, another click of the same button fully shuts.
I've followed the instructions and was able to hook up a winch (on another vehicle) fine but honestly I get lost when trying to program it on my own.
Thanks!

Yes.

What button and channel are you trying to program it to?

I'm thinking the D/R button for channel 3 and the ch3 trim button for channel 4 would be the most intuitive, if those buttons can work that way. I appreciate your help!

 

[losikid]

I'm thinking the D/R button for channel 3 and the ch3 trim button for channel 4 would be the most intuitive, if those buttons can work that way. I appreciate your help!

So you have channel 3 controlling the driver side door and channel 4 controlling the passenger side door?

If so I got an idea. Let's assign both to one switch, the channel 3 trim for example. So when you press forward it opens the right door. When you press forward again it closes the right door. When you pull back on the switch it opens the left door and when you pull back again it closes the door.

So todo this, follow these steps

Scroll to REV, press and hold enter (Go into the key mapping menu)
Scroll to 3, press enter (Select channel 3 trim switch)
Scroll to off, press enter
Scroll to 3 with the Left arrow lit up that is right under the expo square, press enter (Select the left hand side of the channel 3 trim switch)
Scroll to CH3, press enter (Choose channel 3)
Scroll to MO0, press enter (Momentary off)
Scroll to RE0, press enter (Reverse off)
Scroll to PV0, press enter (Previous value off)
Scroll to 3 with the right arrow lit up that is right under the expo square, press enter (Select the left hand side of the channel 3 trim switch)
Scroll to CH4, press enter (Choose channel 3)
Scroll to MO0, press enter (Momentary off)
Scroll to RE0, press enter (Reverse off)
Scroll to PV0, press enter (Previous value off)
Press and hold enter then press back/end afew times

Now the channel 3 trim switch controls both left and right doors (Channel 3 and channel 4). Make sure to adjust your end points before hooking your servo's up to the doors.

 

[joshpit2003]

I'm keen to get 3-axis head-tracking working with my current FPV setup.

Radio:
- GT3B Radio hacked w/ Overkill RC's flashing kit (0.6.1 Firmware)

3-Axis Head-Tracking Unit:
- Trinity External Head-Tracker Unit (Trinity External Head Tracker (3 Axis))

I thought it would be as simple as plugging in the head-tracking unit into the trainer port of the GT3B and having it automatically transmit the 3-axis as 3 different channels. But then I read here: RC Groups - View Single Post - FPV Car and Other Fun FPV Projects Thread: that I need a PPM signal mixer, and need to do some more minor hardware mods to the GT3B to install it. Unfortunately, the PPM mixer that is linked to is only 2-axis. And since that post wasn't a complete walkthough I'm still left scratching my head.

My 2 big questions:

1. How do you propose I go about getting 3-axis head-tracking (ideally w/ the use of my Trinity external unit) working nicely with my hacked GT3B?

2. Did I even need to hack my GT3B for more channels?

 

[honchojoe]

Hi All. I've got a GT3B hacked by Jyi/TZI. Currently it is setup as a 3ch with the 3rd channel used for a winch using the ch3 trim toggle. I've now bound it to a 6ch rx and would like to setup a 4th channel to use the ch3 D/R toggle for a rear winch. How do I do this?

Sent from my SM-G930F using Tapatalk

 

[honchojoe]

Ok so I downloaded a manual. I set the radio to 6ch. I was able to map the D/R button to a channel and set it to Momentary and it works to control my ch3. But I want it to control ch4 in the same manner but ch4 or any other channel was not available to select. I could select ch3 or all the other functions etc. Also the manual I downloaded was obviously for a different formware as it was slightly different. Mine has F061 if that helps.

 

[Hobbezco]

I have channel 5 assigned to the throttle trim buttons controlling an on/off switch for lights. The switch is designed to cycle from off to blink to blink fast to on solid. I have to press one direction, moving from -100-0-+100 to change the state of the light switch. I then have to push the opposite direction to go from +100-0--100 and then back to the other from -100-0-+100 to change to the next setting of the lights. I have to do the whole cycle of 4 button presses each time to cycle to the next setting on the light switch. Going from on to off takes 14 presses back and forth...

Is there a way to adjust the settings to reduce the number of button presses to cycle through the lighting options?

 

[GTSLOW]

How long do hack kita typically take to shop out?

 

[losikid]

I'm keen to get 3-axis head-tracking working with my current FPV setup.

Radio:
- GT3B Radio hacked w/ Overkill RC's flashing kit (0.6.1 Firmware)

3-Axis Head-Tracking Unit:
- Trinity External Head-Tracker Unit (Trinity External Head Tracker (3 Axis))

I thought it would be as simple as plugging in the head-tracking unit into the trainer port of the GT3B and having it automatically transmit the 3-axis as 3 different channels. But then I read here: RC Groups - View Single Post - FPV Car and Other Fun FPV Projects Thread: that I need a PPM signal mixer, and need to do some more minor hardware mods to the GT3B to install it. Unfortunately, the PPM mixer that is linked to is only 2-axis. And since that post wasn't a complete walkthough I'm still left scratching my head.

My 2 big questions:

1. How do you propose I go about getting 3-axis head-tracking (ideally w/ the use of my Trinity external unit) working nicely with my hacked GT3B?

2. Did I even need to hack my GT3B for more channels?

FPV is not a simple, I've never done it so I can't be much help.

The hack probably wasn't needed for fpv...

Hi All. I've got a GT3B hacked by Jyi/TZI. Currently it is setup as a 3ch with the 3rd channel used for a winch using the ch3 trim toggle. I've now bound it to a 6ch rx and would like to setup a 4th channel to use the ch3 D/R toggle for a rear winch. How do I do this?

Sent from my SM-G930F using Tapatalk

Ok so I downloaded a manual. I set the radio to 6ch. I was able to map the D/R button to a channel and set it to Momentary and it works to control my ch3. But I want it to control ch4 in the same manner but ch4 or any other channel was not available to select. I could select ch3 or all the other functions etc. Also the manual I downloaded was obviously for a different formware as it was slightly different. Mine has F061 if that helps.

Here's the manual
http://overkillrc.com/GT3X-Firmware/0-6-1/MANUAL-0.6.1.txt

You need to change the number of channels in the long-ENTER name menu

- Model number of channels and Model reset
    > choose menu NAME and press ENTER-long
    > menu NAME will blink
    > choose "C" for number of model channels or "r" for model reset
	- reset will show NO/YES

I have channel 5 assigned to the throttle trim buttons controlling an on/off switch for lights. The switch is designed to cycle from off to blink to blink fast to on solid. I have to press one direction, moving from -100-0-+100 to change the state of the light switch. I then have to push the opposite direction to go from +100-0--100 and then back to the other from -100-0-+100 to change to the next setting of the lights. I have to do the whole cycle of 4 button presses each time to cycle to the next setting on the light switch. Going from on to off takes 14 presses back and forth...

Is there a way to adjust the settings to reduce the number of button presses to cycle through the lighting options?

Do this,

Scroll to REV, press and hold enter (Go into the key mapping menu)
Scroll to 2, press enter (Select throttle (channel 2) trim switch)
Scroll to off, press enter
Scroll to 2 with the Left arrow lit up that is right under the expo square, press enter (Select the left hand side of the channel 2 trim switch)
Scroll to CH5, press enter (Choose channel 3)
Scroll to MO1, press enter (Momentary on)
Scroll to RE0, press enter (Reverse off)
Scroll to PV0, press enter (Previous value off)

This should make the left throttle trim button cycle through your positions.

How long do hack kita typically take to shop out?

A week or less.

 

[honchojoe]

Thank you Losikid. It was the long press name to set the channel amount that was holding me back. Now front and rear winches working great.

Sent from my SM-G930F using Tapatalk

 

[Hobbezco]

Thank you for your help. Its working perfectly now. It's so nice to be able to run 8 channels on a $50 radio.

 

[ToSte]

Thank you so much for your help, losikid. That worked perfectly.

 

[joshpit2003]

I've noticed a substantial decrease in range with the hacked radio. I used to be able to drive all the way down my block, nearly out of sight without loss of control. Now I get about 3/4 of the way down the block and I lose all control. Anyone else notice this? Anything I can do to remedy it?

 

[losikid]

I've noticed a substantial decrease in range with the hacked radio. I used to be able to drive all the way down my block, nearly out of sight without loss of control. Now I get about 3/4 of the way down the block and I lose all control. Anyone else notice this? Anything I can do to remedy it?

You probably broke the antenna solder joint while installing the header.

 

[joshpit2003]

You probably broke the antenna solder joint while installing the header.

Thanks for the response.

I'll be sure to check that, but I don't believe that is the case considering how careful I was with the installation.

Another thing I noticed was that immediately after powering up the radio, my truck was crawling in reverse.

I had to go into CHANNEL 2 (throttle for me) and trim it to F40+ to get it to stop reversing. That seemed to solve the problem, I just found it a little odd that the radio would default like that so I thought I would bring it to your attention.

 

[losikid]

Thanks for the response.

I'll be sure to check that, but I don't believe that is the case considering how careful I was with the installation.

Another thing I noticed was that immediately after powering up the radio, my truck was crawling in reverse.

I had to go into CHANNEL 2 (throttle for me) and trim it to F40+ to get it to stop reversing. That seemed to solve the problem, I just found it a little odd that the radio would default like that so I thought I would bring it to your attention.

Yes, it is quite possible that it would behave that way since calibration values have changed.

a.) Make sure the radio is calibrated.
http://www.rccrawler.com/forum/elec...ck-question-answer-thread-15.html#post3213031

b.) Then calibrate the esc to the calibrated radio (Make sure trims are set to zero when you do this)