Here’s how I prepare the DSM2 module harvested from the HP6DSM transmitter. The DX4e and DX5e has a similar module and pinout.

How I wire up the HP6DSM module for the er9x DSM2 hack

You can find more information as well as the schematic by Pat MacKenzie here: Spektrum DSM2 module from HP6DSM

  • Basically, you have a 4k7 (4700ohm) resistor soldered to the 3.3v and signal pad of the DSM2 module. (Pins 2 and 6)
  • Then you simply got three wires that needs to go to the appropriate place…
    1. Pin 1 is your ground pin. That’s the Black wire and should be soldered to any ground point on the transmitter. Those BIG rectangular pads in the third pictures above, are a good, easy place to solder to.
    2. Pin 2 is the power pin. It’s the Red wire in the photo and need to be connected a 3.3v power source. It can take power from a 3.3v regulator like the one I harvested from the donor transmitter, as seen in the third photo, or alternatively, a 3.3v uBec. Both the 3.3v regulator or uBec takes power from a suitable source on your transmitter. I have always use the pin (7th pin from the left) that feeds power to the rear module. I cut the trace and put a RX switch on it. Flip one way and power goes to the rear module. Flip the switch the other way and power goes to the DSM2 module.
    3. Pin 6 is the signal pin. That’s the White wire in the photo above. It needs to be connected to your transmitter’s PPM output. A diode is soldered inline as per the schematic previously linked to.
I’ll make another post on how I use a common receiver switch, like this, this or this, to flip the power between the DSM2 module and the module connected to the rear of the radio.