X-Lite Stealth Crossfire

by Rasmus Klattrup, posted on the 10. of July 2018

Introduction

So I decided to take a real good look at the new beautiful Taranis X-Lite from FrSky and come up with ideas as to how I could mod it to suit my personal needs the best. Here is a list of some very simple things I wanted in a perfect scenario:

You should take a look at the following video and if you find it interesting, please read on to discover how I managed to implement all (soon) of the above.


Current status: Works 100%

As this is a work in progress I decided to include this section of the guide. Here I will comment on any questions I might recieve regarding the status of the project.

I probably won't post any more updates on this unless someone reports some issues to me. Happy modding.

Updates


Required components and sacrifices

To do this mod a few basic components are required. Beware that trying to replicate this is entirely on your own risk.

Please be very aware of the risk there is involved with this mod. I destroyed my TBS Micro Module by a soldering mistake and I also managed to fry one of the pots. The risk is very real and it won't take much to be a very costly endeavor.


How it all began

At first I created an enclosure, that would fit a trimmed down version of the Crossfire module, that could be attached to the back of the radio. This was however a bit clumsy and heavy, so in my next iteration I decided to create the enclosure in a way that required it to be lowered into the back shell of the radio.

The idea was to cut out a rectangle in the back of the shell to lower the module as much as possible and then glue the case to the shell of the radio.

This solution is actually very good and I must say this is still somewhat recommended for people who don't feel super safe disassembling the radio and desoldering components. Remember that a complete new shell only costs ~$18 from HorusRC so it's not that expensive to try out in the first place.

Anyways, then it hit me; While looking at spare parts on HorusRC’s website I saw that the back PCB in the radio was called RF board. This got me wondering if the board could be removed as I did not need the FrSky protocol any longer – all my current models use CF and most likely so will any future models.

The RF board hosts the two Pots though, so this was my first challenge. How do I keep these and still remove the RF board? Well, as it turns out the connectors to these Pots are not used on the RF board at all, they are traced directly to the connecter on the bottom of the PCB which makes it super easy to transfer them to some other mount like a 3D-printed bracket.


The guide

This won't be an exact point-to-point guide of how to do this mod. As I went through the process myself, I took pictures of some of the steps as I had an idea of what I wanted to end up with, but a lot of things changed in the process and I did not take pictures of everything. Due to this, some things will only be described lightely - if something is unclear og missing, please let me know and I will add it ASAP.

#1: We start by taking the TBS module out of it's original enclosure. Remove the two screws at the top and open the case. The module is held in place by three small screws and the antenna is simply locked in by the golden nut in the top.

#2: To be able to fit the module inside the radio you need to decrease the distance between the two PCB's that make the module. I suggest you cut the pins as close to the small module as possible. Then you desolder the left over pins from the small PCB and use a solder sucker to clear all the holes. When this is done you should be able to lower the small module down over the rest of the original pins and place it with a distance of excatly 4mm to the bigger PCB. It is very important that the antenna can fit in between the PCB's or you will run out of place.

(Psst! Now would be a perfect time to do the mod where you change the rf power from 100mw to 250mw! I mean, you have everything torn apart anyways. Look for Livyu FPV's guide in the Honorable mentions below)

#3: Remove the module-connector from the TBS module and solder in som ~3cm wires and prepare the loose end to be soldered on to the 11-pin connector from the radio.

#4: Open up the radio and remove the clip and RF board from the radio. In order to remove the RF board you start by removing the tiny module-PCB and then unclipping the internal antenna. Instead of removing the antenna completely, I decided to put a small piece of shrink tube on the connector to prevent any shorts and just tuck the wire in where it does no harm. Now you can remove the four screws and take out the module and the black mountingclip it's attached to.

#5: Remove the 15-pin cable (used to connect the pots) and smaller 11-pin cable (used to connect the module) from the radio. Note that the yellow wires on both connectors are the left-most wire, and is connected to the left most contact on both my diagram images. Only the wires connected to the pads shown on my images are needed and the rest should carefully be removed from the connectors.

#6: Cut the remaining wires on the 11-pin cable and solder them to the TBS module as per my diagram image. Now it's ready to use. If you want, you can now connect it to the radio and test if it binds to your reciever. Just be very carefull that you won't short anyting out with the loose module.

#7: Mount the antenna in the original antenna-hole of the radio. To prevent the connector from rotating when adding and removing the antenna every time you go out to fly, I suggest you add a bit of blue locktite to the base of the connector where the golden nut will be fastened. When this is done it would be a good time to test if the 3D printed mount fits correctly in place.

#8: Now you have to desolder the two trims from the RF board. Take good care not to bend the very fragile PCB on the pots as you desolder them. When they are off, you just leave all the legs in their current position.

#9: Grab 6 pieces of ~3cm wire and solder them on to each of the 3 bottom legs of both pots. You need to be able to feed the wires through holes on the 3D-printed bracket so make sure you don't have too big a blob of solder.

#10: Feed the wires through the holes of the 3D-printed bracket and fit it into the radio. You need to make sure that you glue in the pots in a position where they won't scratch the edges of the holes on the radio. Do a bit of dryfitting and slightly enlargen the upper holes to be able to rotate the pots a bit if needed. When they sit perfectly, glue them on to the bracket.

#11: Solder the wires from the pots on to the 15-pin connector as per my diagram image above. When connected and powered up, make sure to recalibrate the sticks and pots as the endpoints of the ports might have changed a bit now they have been relocated.

#12: Time has come to mount the TBS module in the 3D-printed bracket. Use the three original screws from the TBS case to secure the module in the print.

#13: Slide the bracket into place and make sure it's all the way in. Beware of the cables on the underside, and make sure the mount is as flat as possible on the connectors. There isn't much space to work with, and every mm counts.

#14: On the back of the radio there is a small moveable clip. You have to cut this away to make access to the TBS USB jack.

#15: Now you should be able to reattach the back of the radio. Beware that there are two small taps on the cover that helps to keep the 3D printed bracket pushed into place. You need to make sure all fits correctly when closing up the radio.

Done - happy flying!


More to come?

Yes, there are a few tiny things missing.

Even though you can put the back cover on to hide the module, I'm working on a small 3D print that makes access to the TBS module a bit better. On the same print I'll add a 2S balance connector to enable charging of the batteries while connected. I'm actually almost done with this, but I know a lot of people are eager to view this guide, so I'm trying to push it out as soon as possible.


Honorable mentions

Jakub Steiner who published his findings on how to connect the TBS module to the X-Lite. Without this, I probably would never have gotten the X-Lite at all. Click here to watch his blog

Whiffles over at RotorBuilds.com for giving us a complete teardown guide of the X-Lite. This gives us a superb overview before juimping into the radio our self. Click here to watch his guide

Livyu FPV for sharing with us how to mod the micro module to send with 250mw compared to the 100mw it ships with. Click here to follow his tutorial


About me

My name is Rasmus Klattrup and I'm a 35 year old guy from Denmark. I have been flying race quads for several years but have more or less moved on to fixed wing racing and long range smoothness. I love pushing boundaries and I must say this mod is a clear proff of that. ;)

Feel free to reach out through one of the following platforms!