HP6DSM Module Wired Up

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.







38 responses to “HP6DSM Module Wired Up”

  1. cloudflying Avatar

    Best write up yet! Thanks!!

  2. HacksMods Avatar

    Nice splash screen! :)

    1. Marc Cepeda Avatar

      Hehe, thanks. Just curious if you know of a way to test if the X1TXN is good or bad? I think I might have damaged mine when putting things back together after installing my backlight.

      1. HacksMods Avatar

        Best way is to plug it back into the original TX. It’s usually not that easy to kill, so it must be something you’re overlooking. Wishing you the best.

        1. Marc Cepeda Avatar

          D’oh! Cannibalized it to death (lol). Oh well. Cheaper to buy a FS Rx than another HP6DSM.

          1. HacksMods Avatar

            Interesting. Cuz the HP6DSM only require you to unplug from the original radio. Unlike the DX4e which required you to unsolder each of the pins. So no luck after putting it back into the original TX huh? Sorry to hear that.

          2. Marc Cepeda Avatar

            Yeah, I gutted the HP6DSM for the switches and wires and other goodies, so there was no turning back. Since DHW hadn’t received any of parts I need to get my 450 Sport back in the air, I decided to buy an mCPX. I cut the module out of the DX4E (less risky to just cut the pins, imho, compared to trying to desolder w/out a wick) and put into the Tx. All is good once again with my AR6100e bound, but now I’m trying to bind the mCPX to it and failing. If it’s not one thing, it’s another…

          3. HacksMods Avatar

            Sweet. I agree…it’s easy to get the module out of the HP6DSM, but on the DX4e and DX5e…it’s better to just cut the pin. Less risk IMHO.

            DSMX for the win. :)

            What’s the issue with the blade tracking? You set up the pitch and swashplate the same way you would on a Spektrum radio.

          4. Marc Cepeda Avatar

            Cutting was definitely the way to go, and yes. DSMX FTW! I smell BeastX on the horizon.

            Turns out the last “bump” with a wall before I gutted the DX4E broke my main gear. It wasn’t something I was familiar with, so I took it to my LHS this morning. The guy pointed it out (it looked fine to me until he showed me what was wrong…really tiny crack), and popped a new one on. Flapping fixed. Got some pink blades and green skids on there. Raring to go!

          5. HacksMods Avatar

            Here’s a secret. The v929 is a clone of the Blade mQX. The mQX uses the same main gear as the mSR, mSRX and mCPX. Therefore, the v929’s main gear is a good aftermarket part. I believe it’s a lot cheaper than the mCPX version. So possibly worth a shot if you find yourself breaking many main gears while learning CP.

          6. HacksMods Avatar

            Since you think you killed it and you’re in the area. You should let me take a look to confirm. :)

  3. Heli Pad Avatar
    Heli Pad

    Nice write up. Clear pictures were very informative.

    1. Allen Arguio Avatar

      Hi –
      I just completed a FS-TH9X (running Open9x-r1641 EEPR:212-0) expansion to support DSM2 by harvesting the HP6DSM module from a Spectrum Dsx5e transmitter. I wired everything per the guide and I can bind with both PPM and DSM. The issue is when I bind with my mSR X it seems to bind (blue light blinks fast then turns solid when bound) however it then soon starts to blink slowly, about once a second and I don’t seem to have any control.
      My setup is as follows:
      Protocal: DSM2 DSMx
      RxNum 00 RANGE
      Ch Order: RETA
      Mode: 2
      Not sure if I am having a hardware or setup issue….Can anyone help?

      1. hacksmod Avatar

        I helped someone on the HeliFreak forum and we found that the Open9x firmware didn’t do a good job of supporting the timing that DSM2 needed. So he had lag. Once he flashed er9x, his problem went away. I recommend er9x to see if that works out. Then once you confirm that all your wiring of the DSM2 module is properly done and working. You can explore Open9x.

  4. Thorsten Avatar

    Hey there,

    could you please explain a bit more the way you achived to make the power-source for each module switchable? I can’t get what you mean with pin 7 and cut the trace…;)

    1. hacksmod Avatar

      Did you see this photo yet?

      You basically cut the trace that powers the rear module. Then you can tap into it with a switch.

      Let me know if that makes sense or not.

      1. DudeInMyrtleBeach Avatar

        By the looks of that picture, since the switch only cuts power to the rear module, the dsm module is on all the time – is that right?

        1. hacksmod Avatar

          No, main power goes into the center pole of the switch. Then you flip the switch one way, power goes to the rear module. You flip the other way, the power flows to the internal DSM module. On, and Off. Simple. Hope that makes sense.

  5. Thorsten Avatar

    I didn’t get the whole pic…lol. Now its clear! BIG THX for the photo!

  6. Ustas69 Avatar

    Can I use X1TXN B2 version from JR DSX7 radio? I tryed to bind Orange 6 channel receiver but it no binding. How to check working module or not?

    1. hacksmod Avatar

      If that radio can bind to DSM2, then you should be able to.

      However, rather than sacrifice a DX7, perhaps it’s wiser to sell that radio and use the proceeds to purchase an OrangeRX DSM2 module from HobbyKing instead?

  7. old82cutlass Avatar

    i have a question concerning the dsm2 module swap and binding. i know i need to hold the trainer switch in while powering up the radio with the rx plugged in and blinking rapidly to bind. but ive tried this and its not working. i have a flysky 9x v2 with the HP6DSM module from a Spectrum and running er9x. ive checked power to the board and its getting power and ground when i switch it over. the flysky rx works just fine. any help would be appreciated.

    My setup is as follows:
    Protocal: DSM2 only
    RxNum 00 RANGE

    1. hacksmod Avatar

      Make sure to let go of the trainer switch once the radio is turned on.

  8. old82cutlass Avatar

    yeah tried that still no bind. ive also tried with 3 different nano boards and none of them want to link.
    i know my hp6dsm board was working when i pulled it out. but maybe it got damaged. also i installed the antenna from the hp6dsm controller on the back and connected that to the board.(didnt know if that would make a difference) and i was wondering witch way the diode had to face. i have it with white strip on the 9x board side. would it hurt to flip it?

  9. old82cutlass Avatar

    one thing i just noticed was when i turn the switch for dsm2 on while already linked to a flysky rx the plane still works but all the servos go a little haywire. backwards diode?

    1. hacksmod Avatar

      Sorry for the delay. I originally read your latest comments while out with the family. And I didn’t understand your question about the diode.

      Having read it again. I would like a photo if you could provide that. So we’re on the same page. I’d like to think that your HP6DSM module is still fine…and that the problem lies somewhere else. :)


    2. hacksmod Avatar

      For clarity, in case you mean the diode here. In this photo, the diode white line is on the left. You can see the silver line on the diode that denotes this.

      Image of diode link

  10. old82cutlass Avatar

    i tried to send you an email with the pictures in it. not sure if i got the right address i used mailtomods@hacksmods.com let me know if you got it.

  11. MephistoPheles Avatar


    Very interesting hack, i was wondering if this could work with the latest turnigy 9xR?


  12. pouakai Avatar

    I don’t understand how this Hack could work as pin 6 on the X1TXN module is (according the User Manual) the ‘Slave Select’ pin of the 4-wire SPI digital interface. The module doesn’t have a PPM Input…


    1. hacksmod Avatar

      Because the ER9x firmware isn’t sending a PPM stream. It’s sending Spektrum’s native stream. Which is what the X1TXN module is expecting. So it looks like a native Spektrum transmitter as far as the X1TXN module is concern.

  13. Pouakai Avatar

    But SPI is a 4 wire interface and additionally requires mosi,miso,&sclk connected in order to talk to the cyrf6936. It cant work with only SS connected as far as i can see from the datasheet. What am I missing ?

    1. hacksmod Avatar

      My original post has the reference links:

      Here is the historic work and likely the answer you seek:

      1. Greg Avatar

        Hi Hacksmod, hope you’re still active on this blog..

        I have to confess that I’m a copy/paste electronics man (knowing a little bit can be dangerous) so I follow in the footsteps of others.

        I’m hoping to use your pics here to reproduce the same in my 9x now upgraded with the 9xtreme board.

        One thing I noticed in the pics is seemingly a second resistor coming back from the switch to pin 3 – is this necessary as others don’t seem to refer to this?

        My second question is that long ago I installed the 1k resistor to pin one to circumvent the early issue of trainer/simulator output, do I leave this in or must it come out?

        Many thanks

        1. hacksmod Avatar

          Hi Greg, gosh… I didn’t realize my email forwarder have been broken. Didn’t see your comment until I logged in today. Ooops.

          I think the best method at the moment is to upgrade the ER9x firmware that can support the 4in1 multimodule. That’s what I am currently using and it’s a blessing to have access to all the protocols. Here’s the one I currently use.

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