The Walkera Devo 7e is a good compact transmitter. Install the Deviation firmware, and you have an unbeatable transmitter that supports many protocols. The one wishlist item that owners have is that the TX can be use for longer range flying. Fortunately, the gurus hacking on the Devo 7e found that by shorting a single diode, you bypass the intentional handicapping of the radio transmission, and increase the power output by 10x. Making it on par with it’s full range siblings, the Devo 10 and Devo 8s.
All it takes is to remove the metal shield to access the diode that needs to be bypassed.
There’s a large amount of solder so the risk for solder splashes is high. Therefore, eye protection is important.
I start by putting on eye protection. Then add some additional solder to each of the two corners you’re going to remove first. The additional solder helps the solder blob stay heated and molten. Then quickly, move your solder iron back and forth between two points. Use a hobby knife or tweezers to lift one side of the shield. Then simply repeat for the second pair of solder joints and the shield will come off quite easily.
Then it’s just a matter of identifying the diode and shorting it. Before doing so, it’s a good idea to do a range test to get a reference of how far the stock radio transmission is able reach. Important for testing whether your mod was successful at the end.
/update 2014-01-01
The safest way we have found to accomplish this is to use a conductive ink or compound. Such as the stuff used to repair the defogging lines on a automobile rear window. These can be found for about $8-11 at most automotive parts store. With the conductive ink, you can just paint diode and make sure it’s covered well enough so both ends of the diode is now electrically connected.
I have seen circuit writer pens with conductive ink. Generally pricey at $20. You press the tip in to release the ink. However, do not press inward over the circuit board. A flood of ink may pour out. So press over a piece of scrap plastic to see how much flows out or create a drop. Then just transfer and short the diode. Build it up to ensure you have good coverage.
/update end
Now, for those who intend on soldering because it’s what they already have on the bench and do not want to buy conductive ink…please take note to help mitigate accidents and increase your chances of being successful.
Note: the area is very cramp with surrounding SMD. I suggest you use tape, such as Kapton, or liquid electrical tape, or something that will help mitigate unintentionally removing of a surrounding SMD.
There are several methods to short the pads the diode is soldered to. Nowadays, the community feel it’s best to steer people towards the use of conductive ink. (See the updated section above.) It’s easier to get right and not risk accidentally and unintentionally desoldering the surrounding smd components.
Alternatively, you can simply solder a thin wire on each end of the diode. This way, you can reverse the changes. This is how I am modding Devo 7e nowadays:
And here’s a photo of how I first did the mod. I’ll include it for historical purpose. Hidden by default so it doesn’t clutter this post and confuse newbies with too many optional ways to accomplish the mod.
Click to show original method
I originally accomplish the mod by using solder to bridge the two points after I removed the diode that was there. I used a small wire to help the solder flow and bridge the two points. See image below.
Once you are done bridging the two points, test the radio and ensure you are still able to bind to and control the R/C. Once you deem the mod has been successful, it’s important to put back on the RF shield.
I do this by cleaning up any solder so the shield can sit flat. Then it’s just a matter of adding new solder so everything looks the way it did before you removed the shield.
Lastly, make sure you edit your tx.ini file and enable the additional power.
/update 2014-02-16
The latest Deviation firmware have moved the [modules] section from the tx.ini to a hardware.ini file. So locate and edit the [modules] section in the appropriate file depending on which version of Deviation you are using.
/update end
(Tip in layman’s term: A semicolon preceding the line means that line has been “commented out,” therefore it’s not read. Remove the semicolon to “activate” the line)
[modules]
has_pa-cyrf6936 = 1
Finally, do another range test to ensure your mod is successful before you close everything up.
Here’s a thread discussing the mod with some graphs of the increase in power output.
Thank for the article, i had searching any info about this problem of Devo 7e. ) How increase the range after this upgrade? Where i can find the tx.ini ? Thank!!!!
The tx.ini is already on your radio if you already flashed the Devo7e to Deviation. Put your radio in USB mode and connect to your computer. You will find the tx.ini there.
Hopefully I answer your question properly.
Thank! But one much important qvestion – range increasing? ))
It sounds like you didn’t read the manual. It has the instruction on what you need to get Deviation installed.
First, flash Deviation firmware. Then put your radio into USB mode and copy the content of the file system zip to your radio. That file system contains the tx.ini file. The latest Deviation moved some of the settings from the tx.ini to a new file call hardware.ini. You should see the two file in the file system.
Because i purchased the Devo 7e and want to know – sell this right now or a murdering a little, before i’ll brake this finally by my “tuning”? )))
Sorry, I don’t understand what you mean. :(
Hi, just wanted to share my experience of applying the diode mod to my 7e Tx with original firmware.
First thing – this is a very challenging mod, the pictures shown make it look fairly easy but as said the components are very small – take care.
I used a 60w iron to remove the shield & 30w to short the diode.
Before shorting I measured the component resistance of the in-circuit diode and got same 14.8K ohms from both polarities. Was expecting a much lower resistance when the “diode” was forward biased, this had me puzzled?
Decided to press on and using tweezers shorted the diode successfully, for me this seemed the safest option.
I measured the 7e current drawn before and after mod and this does show some expected results.
Current (after bind bleeps etc.) before mod was 92mA and 152mA after mod, so we are defiantly using more power. Still using the original firmware but plan to flash to Deviation soon.
Hope these readings help any others considering the mod.
Thanks for sharing your experience. Good job on the successful mod. :D
I am in the midst if performing this mod. I have some conductive ink coming from China but since my v202 fc frankenquad is ready I decided to pop open module and maybe take a swing at soldering the diode. I consider myself an average solderer. I pulled off the mods necessary to install er9x on my other tx, I solder motors to my ESC, ect. I think I will wait for the slow boat on this one. This diode is really small! I practiced on a old sound card my technique but this diode is half the size of my practice work. I just wanted to give fair warning to all tearing into their 7e’s that without ink this mode is no cupcake. And compliment the photographer for such a great view. The pic’s make it look much easier than it is in real life.
Hehe. I wish I can solder for everyone instead of just the local peeps who as for help. :)
How come I don’t get any credit for my soldering skills in addition to taking a “great view” of the mod. ;)
does this upgrade works on devo7 too or just devo7 e?
Just the Devo 7e.
The older Devo 7 is one of the radio no supported by Deviation.
i tryed to open my devo 7 but seems different, anyway i see devo7 and devo7E both have -5 + 20 output
The Devo 7 does not need the range mod. It’s already a full range transmitter.
Wow, thanks for this.
Would you happen to know if there is a mod for a Devo 6 TX?
I know, I can turn up the TX signal to +20dB but I use the TX for RC yachts and I could do with an even stronger signal f possible.
Best and thanks again.
As far as I know, the Devo 6s is already a full range transmitter. I am surprise if you’re running into a range issue with it.
After doing the diode bipass. Must I install the Deviation firmware, or can I make the necessary changes to the existing software?
Thanks
Dave
If I were to use the stock firmware. I would be transmitting at full power correct?
What problems does that condition create? The Devo 7e wouldn’t be putting out more then 150mW would it?
Thanks again.
I am not sure. Please ask the question in the http://deviationtx.com/forum/
You will get a better answer from the developers there.
Will this Range Mod have any affect with a installed A7105 (Hubsan)?? Or is it just for all the Stock protocols, Walkera, DSMX, etc?
I was wondering the same thing, Terry. I could be wrong, but my sense is that since it is a separate TX board with optional power amplifiers, this range mod will not have any effect. See this comment here, too:
“BTW, the range mod on the inbuilt CYRF6936 module of a Devo7e has nothing to to with any range on the A7105 transceiver”
http://www.rcgroups.com/forums/showpost.php?p=30514704&postcount=2576
Yes, you are modding the built in CYRF transceiver to extend it’s range. And that is responsible for Walkera, DSM2 or DSMX.
The A7105 is a separate transceiver…and you can buy them with the power amp circuit. No range mod necessary on that.
We co’udlve done with that insight early on.
Do you have a clue what component the other black one is below the diode?
I got a modded 7e, however, range is only a few meters. When trying to fix it, I noticed that the
other black component below the diode is missing.
Looks like a resistor to me. I don’t know what value. Ask your question in this thread. Perhaps they can help. The OP had range issue too. He found the culprit was that the module wasn’t receiving the correct 5v. Instead, it was only getting like 2v. Therefore, the problem isn’t directly related to yours…but since he was diagnosing his issue, he can likely tell you.
Also, he said the diode we bypass for the range mod is really a resistor. This argument comes up every now and then. If it really is a resistor…perhaps you can use it to replace the one that is missing. Maybe they are the same value? I’ll see if I can desolder mine and measure. Let you know if I do.
http://deviationtx.com/forum/6-general-discussions/4178-dsmx-dsm2-zero-range-solved
Wow, thank you for your fast reply! Problem is, the previous owner already replaced the ‘diode’ with a blob of solder, so no chance for me to swap those components.
Since there seems to be no schematics around, how did you find out about this mod???
Anyway, meanwhile I ordered an upgrade module but of course I’d be glad if I could make mine work again.
There’s a link at the end of this blog post you commented in. It links back to the original thread the mod originated from. More info are within that thread.
tnx a lot. Went through these threads already, but there are 5v on mine :-( That would have been to easy…
Sorry. What I mean was that I was hoping that since the OP who started that thread was troubleshooting his issue, that he may know the resistor value off hand.
Anyways, I opened up mine. And desoldered that resistor to isolate it. My Fluke multimeter read 10kohm.
Hope that helps.
BTW, make sure your hardware.ini has been updated to reflect that the range mod was done.
i.e. Change
has_pa-cyrf6936 = 0
to
has_pa-cyrf6936 = 1
Guess what? After I opened up the radio and found out the value of your missing resistor…I run across this post which confirms my own finding.
http://www.deviationtx.com/forum/3-feedback-questions/1439-removing-shield-and-diode-7e-for-better-reach?start=20#11541
Wow! Thank you very much, haven’t expected such support!
Now I need to find a 10kOhm 0402 resistor and somebody with a steady hand :-)
I guess, this 10k resistor belongs to the RDA T212 PA/LNA circuit, right?
However I wasn’t able to find a datasheet, let alone a reference design.
Thanks again!
So I’m looking at mine and mine is missing the 10k resistor as well, but I know for sure I didn’t accidentally remove it. Are the newer ones just coming without it?
Maybe the newer ones are just coming without it.
Closest thing to a datasheet is what PracturedBlue shared here: http://deviationtx.com/articles/17-hardware-documentation/18-devo-7e-hardware-connections
Im would like to know if I understand what Im suppose to do before I attemp this?
1. Open Devo 7e
2. Unsolder RF shield
3. Break off the litte button looking part of the diode in picture above.
4. Use circuit writer pen to make a line connection where the button looking part was.
5. Download Deviation firmware
6.Not sure how to put TX in USB mode?
7. then I remove a semicolon from hardware.ini. this parts confusing?
8. The resolder the RF shield.
9. Then Im done?
Do I need a higher decibel antenna like 5db? If so whats a link to a good one thats compatible?
Dear HacksMod, first I see in your RF module is Walkera’s common error – both chokes at CYRF6936 are 1.8nH. This one at pin 10 should be 22nH.
Sorry my poor English…
Czarek.
Thank you. I’ll have to digest what you mean. Going to post on RCGroups thread to see if anybody can make sense of it.
http://www.rcgroups.com/forums/showthread.php?t=1918045&page=256#post32723941
hello.
is it possible to use the hack with standard devo 7e firmware?
I recall this question coming up many times, but I don’t remember the answer. With Deviation firmware, after you bridge that resistor…you also tell the firmware that the range mod has been done.
Maybe a good question for the http://deviationtx.com forum.
Hi, I just did the range mod and everything seems to be fine, but I have a question about checking if it worked. Is it possible to check it by measuring current flowing through the tx?
When changing tx power in the deviaton menu its is something about 92mA on the lowest seting, and 109 mA on the 150mW setting. Would it be changing if the mod was not succesfull? OR even without the mod the current changes with settings?
I recall reading that the current does change as it’s outputting more power. I can’t seem to find the post. But definitely, the best way is to range test with the model itself. This holds true for all RC radio actually. Modded or not.
And what range should I expect if the mod was succesful? And what if it was not?
Ahh I wish i did a range test before the mod ;(
Or maybe I should ask differently – would it be possible to fly a quad ~12 meters on the 100uW setting, if the mod was not succesfull?
Shit shit shit, I’ve been stupid and accidentally desoldered another SMD component as you can see here: http://i.imgur.com/0kShEkq.jpg. Do you know what kind of component that is? It looks to be another diode, but I’m not sure. AARGH, I’ve done tons of soldering in the past but never this small, I’m embarrassed that this has happened :-/
The component’s gone btw, I unfortunately lost it. Now the Devo 7e TX isn’t functioning anymore. The a7105 and nrf24l01 I built into the Devo 7e following your hacks both work just fine! But my DSM2 receiver isn’t binding anymore.
Tips? Ideas?
Darn. That happens to the best of us.
I think they are all resistors. Let me see what value that is.
Looks like it’s 10kohm resistor. Just like the one you’re bridging for the range mod. The resistor that we have been calling a diode.
Is there a similar way to increase the range for the Walkera F12E transmitter? This CE version is only 10 mW.
I am not familiar with that model transmitter. Sorry.
Maybe I overlooked something, but I can’t seem to find the answer. Do I have to remove the diode or can I leave it in place an just “draw” on it with the conductive ink? Also the diode in question seems to be white in my transmitter does that make a difference?
Sorry if I have missed the answers to these questions, I have been searching for answers quite a while now without finding any.
I painted over the diode (without removing it) and the range did in fact improve. Only problem now is, that the voltage indicator on the top right corner of the screen seems to jump between values (up to 0.2V difference). Is that normal or did I break something?
My firmware is the stable 5.00. I didn’t notice any Voltage jumping before the mod.
Yes, you can paint over the diode. And the fluctuation is normal.
Thanks for the reply! Keep up the good work.
You can paint over the diode.
So if we can paint over the diode, does that also mean we can leave the diode and solder a thin wire to bypass over the diode?
Correct, that’s what many people do. Leave resistor(diode) in place and paint over it with conductive ink.
has anyone modded a devo f7? I want to use that with all my quads because I like the way it feels, it has the full transmission signal and the LED screen.(and i own it already)
hi there! I tried to do the range mod and it seems to be bridged correctly but after re assemble it its not binding to a dsmx receiver.. that receiver works with a spektrum tx without any problem, do you know how can i test if the current flows through?
Hello, I just purchased the Walkera Rodeo 110 with the Devo 7. Does this remote have full range or do i need the mod ? Thanks, Josh
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