Modifying the Walkera 4-Channel Transmitter

This page shows how to modify the Walkera 4-Channel Transmitter to interface to the PC via the microphone socket and work with PRE-Flight. It requires only 2 solder joins and the modification is completely reversible (as long as it is done properly). The 4 screws at the back of the Transmitter are the only screws removed. The removal of circuit boards and other delicate components are not required.
Important note: Read all the instructions before attempting any modifications! Also, read the following conditions before starting:
1) The modification will only work with the full versions of PRE-Flight (including the Standard Edition, Dragonfly Edition, Blade Edition, and T-Rex Edition) - it will not work with the demo version. It will not work with any other simulators.
2) Opening your transmitter will probably void any warranties.
3) The modification has been extensively tested on several transmitters and proven to work but due to the nature of the modification, there are no guarantees that it will work with your transmitter.
4) The modification applies only to the 4-channel Walkera Transmitter - the Walkera 6, 7, and 8 -channel transmitters do not need to be modified to work with PRE-Flight.
5) The modification requires the PRE-Flight Interface Cable which comes with the full version of PRE-Flight (if you specify the Walkera 4-channel transmitter). Order PRE-Flight here
6) Read all warnings in this modification to avoid problems.
7) This modification is supplied as is. The author assumes no liability for damages, direct or consequential, which may result from this modification or from the use of Pre-Flight.
Checking your Transmitter:
Make sure your transmitter is a Walkera 4-Channel TX. 4 Channel transmitters are identified by the 8 DIP switches at the back of the case:

If you have a different number of switches, this modification is not necessary - just specify the proper TX when ordering PRE-Flight.
Important Notes on Modification:

1) The modification requires some soldering skills.
2) Excessive heat in soldering may damage the transmitter.
3) The transmitter is a fragile electronic device. Care is required in following the procedure below.
4) The transmitter components are susceptible to electrostatic damage. Avoid touching any components unnecessarily.
5) Make sure your hands and tools are not electrostatically charged before proceeding.
Tools and Materials Required:

1) The Interface Cable from PRE-Flight. See this link to order.
2) Soldering Iron - about 20 Watts rating.
3) Solder.
4) Small Philips head screwdriver.
5) Some electrical tape.
6) Needle nose pliers.
7) Small ruler for measuring in millimeters.
8) A 3mm drill bit and drill may be required to enlarge a hole slightly.

Procedure:

Note: The Photos are of the Walkera Dragonfly #4 Transmitter. Your specific 4-Channel Transmitter may differ slightly.
1) Remove the batteries.
2) Unscrew and remove the antenna.
3) Remove the 4 screws that hold the back of the Transmitter case with a small Philips head screwdriver:

4) Depending on your transmitter, you may have to remove a plug to take the two halves apart. Remove the plug by carefully pulling on the plug body. Avoid pulling on the wires:

5) Open the two halves of the transmitter. Take care not to pull wires apart.
6) Thread the free end of the Interface Cable thru the indicated hole below:

7) If the hole is too tight, drill it out with a 3mm drill bit.
8) Pull the end out to about 200mm.

9) Loop the cable as indicated to keep from being pulled out.

10) Solder the two ends of the cable as indicated. Note the red end and yellow end must be hooked and soldered into the correct points. Make sure the original connections are not broken. Do not use too much solder as short circuits may occur.

11) Tape the cable to the case as indicated to keep the cable flat. This keeps the cable from fouling the stick assembly:

12) Re-attach the plug removed from step 4.
13) Close the case and re-install the 4 screws.
14) Re-install the antenna and batteries.
This concludes the modification. Reversal of this modification is a matter of de-soldering and removing the cable interface.
Warning: Do not connect the plug into any socket other than the microphone socket of a PC. Damage may result to both TX and PC if this is not observed. Also, do not apply static electricity to the plug.
Turn the Transmitter on and insert the chrome plug into the microphone socket of the PC when prompted by PRE-Flight. The cable may be coiled and secured by tape when not it use.

What's News?
Want a sim compatible with the Walkera Dragonfly Helicopter #36 , #35 , #22E , 36# , 35# , 22E# , 22E - both CCPM and non-CCPM? Click here.
The PRE-Flight Blade Edition now available. Click here.
Looking for Simulator for your T-Rex Heli? The PRE-Flight Trex Sim is now available! Click here for the best simulator for your Trex Helicopter.
The Blade CP 6-channel CCPM Transmitter by E-Flite is now supported by PRE-Flight sim. Click here.
Need a Specific Model in PRE-Flight for your Club or Company? Have a Custom Model made up for a very reasonable cost! Click here.
3D Photorealistic ScreenShots! See New 3D Photorealistic ScreenShots Page.
Fly in your own Virtual Flying Field Find out how to re-create your flying field - visit the PhotoField Page.
Official PRE-Flight Screensaver now available for free downloading! See Other Downloads.

eDimensional's 3D Glasses give you the total immersive experience when used with the PRE-Flight Interface!