Looks like I broke my Devo 7e

Last night I installed 2 3-way switches and wired them up to be 2-way. That went well and everything worked.

This evening I thought I'd finish the job and wire in the other position to both switches. Somewhere along the way it seems I have damaged my Devo 7e. With the transmitter turned on, whenever I press ANY of the buttons all I get is a beep and nothing else. They don't activate anything.

I have reversed the changes, but that hasn't fixed the problem.

Is my Devo 7e toast?

First thing to do is post up some CLEAR, macro shots of all the areas you worked in for us to help.

Other than that, want to sell it?

Cereal_Killer wrote: First thing to do is post up some CLEAR, macro shots of all the areas you worked in for us to help.

Other than that, want to sell it?

I'm sure that I posted a reply to this to say that I figured it out. I had bridge a set of pins accidentally.

So nope, don't want to sell it

Thanks anyway man

Glad you figured it out......On another note, I didn't realize just how small the surface mounted diode for the range extension mod was until I removed the metal shield. WOW, now I understand why people were messing it up. That being said, I used the conductive ink and now have the full 150mW power

brew99 wrote: Glad you figured it out......On another note, I didn't realize just how small the surface mounted diode for the range extension mod was until I removed the metal shield. WOW, now I understand why people were messing it up. That being said, I used the conductive ink and now have the full 150mW power

It's absolutely tiny. I can't see it unaided. I desoldered all 3 of those diodes by accident and burned the module's PCB. I ended up pulling the module (yanking the solder pads in the process!) and soldered in a connector to use with my other Walkera TX's socketed module. I've got full range but it's only a one-way link and the wiring is disgusting. But, it works.

... And that's why I'm going with the ink. When it arrives...

Yup, that thing's an 0402 size RESISTOR (no one's sure why / where it started being called the "diode mod" as it's not a diode at all lol).

I've done a few more since I did my first. Now I just add a solder blob right over top, I dont remove it first anymore.

Cereal_Killer wrote: Yup, that thing's an 0402 size RESISTOR (no one's sure why / where it started being called the "diode mod" as it's not a diode at all lol).

I've done a few more since I did my first. Now I just add a solder blob right over top, I dont remove it first anymore.

I know people say how small that thing is, but it is honestly MINUTE!!!

So, I managed to not only accidentally un-solder, remover and LOSE that resister, it seems that I have done the same to the resister directly below it. This is despite my having covered the surrounding resistors in electrical tape, leaving only that one exposed, so that I didn't do that.

The transmitter still works and it still controls my quad, but I just did a quick range test and I am still getting about 30m (maybe less now actually). So that would appear to be the end of my Devo 7e as a useful transmitter.

Later in the year I going to be ordering a Tx for my son when we build his quad, so I think I will do that now and be done with it. It's fair to say that I won't be getting another Devo 7e. Most likely I will go with an Orange T-six. I'm done with modding stuff. Not that I don't enjoy doing it, but the possibility that it will go wrong and I destroy costly items is far too great for me.

With that said, I'm open the possibility that all is not lost with the 7e, if anyone has any great ideas?

You can get a 8s module for the 7e, so it shouldn't be junk just yet

it's a 10K resistor, I can replace it for you if you're interested...

As mentioned above BangGood does sell a Devo 8S upgrade module, only thing is (one) it's not a direct fit in the 7E and (two) last time I checked they dont actually stock them, dont expect it any time before september even if you order right this second...


So anyway, want to sell it lol?

I've ordered from Bangood and they reckon they've shipped the module and other bits

So at this stage, I'll hold on to it

Cereal_Killer wrote: it's a 10K resistor, I can replace it for you if you're interested...

What does that resistor do? The transmitter is still working as it was... If I were to simply bridge the resistor, would that be bad?

DoubleQuad wrote:

Cereal_Killer wrote: it's a 10K resistor, I can replace it for you if you're interested...

What does that resistor do? The transmitter is still working as it was... If I were to simply bridge the resistor, would that be bad?

Who knows exactly what it does. With a value that high I certinally would NOT just bridge it. 10k is pretty high resistance, a bridge could be a dead short if it's + to GND, my suggestion would be to get it replaced before trying to actually fly anything with it. 10K 0402's are super common, you can probably take some broken component apart and find some...
Note you can pretty easily fit 0603'a onto 0402 pads when they've got room around them, not that 0603'a are big, but that are somewhat larger and when you're talking about this tiny of parts even the slightest size increase helps (an 0805 will NOT fit).

I would NEVER use a compromise radio to FLY something, use it on a ground vehicle for a bit to ensure it works. You know, on something that doesn't fall out of the sky if there's an issue.

He said ..." which is directly below.." and that depends on the orientation you are looking at the rf modul.
There a two in this area. So, which one is meant?
One is on the trace to the LNA switch pin at the T212 and one shares the trace with the to be bridged one and
ends on the other side at V2 on the antenna switch (S79).

For more information please download - RDAT212.pdf -and the file from here...2403schem.pdf.
www.deviationtx.com/forum/3-feedback-que...enMode=desktop#35146

Thanks guys
I'm actually not too worried, given that I have ordered the new module etc to replace the one in question. I just figured that if bridging the resistor wouldn't do anything bad, I'd give it a go and see what happened. If bad things were likely to happen, I'd leave it.
Anyhoo, here's my version of the photo posted by aMax, showing the two resistors I removed.

I see, this one is for the LNA & RX switch on the PA ( T212)
If the control voltage on this trace does not exceed +4v (max), it might work again.
Normally this is 2.8~3.0V.

Thanks

Does that in any way affect the output?

In other words, if I have successfully removed and bridged the target resistor, I should now have 150 mW of power. I don't appear to. Could this missing resistor be the reason why?

Maybe the PA is blocked while LNA and the RX switch is flooting or not at the correct level of 0V.

Edit: Logic is like this... and if the resitor acts as a currend limit, it should be inserted. Sorry, I have no circiut diagram of the 7e RF module, only saw this on the 2403schem.pdf.

aMax wrote: Maybe the PA is blocked while LNA and the RX switch is flooting or not at the correct level of 0V.

Edit: Logic is like this... and if the resitor acts as a currend limit, it should be inserted. Sorry, I have no circiut diagram of the 7e RF module, only saw this on the 2403schem.pdf.

Thanks - I really appreciate your efforts

I have the conductive ink now which I should have just waited for the in first place. Once the new module arrives I'll try the ink and if it works i'll put the new one aside for when I get my son's Tx. If it doesn't I'll fit it...