DSMX/DSM2- zero range [SOLVED!!!]

...digging out this, might be interesting for you.
www.deviationtx.com/forum/7-development/...evo7e-work?start=120

....and yes, there should be a different current draw.
Therefore check these yellow traces.
www.deviationtx.com/forum/3-feedback-que...each?start=140#28629 .

6 month later update: It turns out that diode is bad, replaced it, removed bodge wire and all is well!



SOLVED!!!

I figured it out! aMax thank you for your links, they really helped!.

The issue was that on the 5v pin to the factory module I was only getting 2.2v. No idea what could of caused that but I used a bodge wire to apply 5V directly and I HAVE FULL RANGE!
What I need to do now is find a proper 5v source I can supply with devo module with and button it back up and (after some final testing) FINALLY fly my tri!

aMax I seriously owe you man, if you're ever threw Columbus Ohio let me know, the least I can do is buy you a beer!

......cheers !

This is where I pulld 5v from.


Here's the initial range test (vid is still processing. Will be live in a minute or two) EDIT: didn't realize how windy it is, video is pretty much useless but you can see what's going on if you have nothing better to do with 5min.

Not really sure..
but if you need to do a workaround, please get the power from behind the MosFed.(IRLML6401).....or your rf module will be powered on all the time.
www.deviationtx.com/forum/3-feedback-que...lown-regulator#27648
Look at SadSack´s circut diagram. (jumper top right )
Edit:
Test if your powersource is switched off by the tx power switch.

That was just right at first, I've since moved the 5v source over to a much closer pad that is switched. I did test off current draw with it like that and it was freaking 9mA so you'r absolutely right. For anyone else looking at this take aMax's advice and don't use that pad in the picture the Orange wore comes from, again that was only for testing, I'd highly advise finding a 5v source that's regulated and at the very least switched via a FET with the tX's power switch.

Here's a range test. This was in DSMX mode on the Orange, I plan to test the lemon's range (in DSM2, since DSMX still doesn't work) soon too. I also need to test this one at 100 and 150mW but for one I ran out of room and two this is a little 280 size tri, 335yds is more than enough, even if i stepped up to the higher output levels I wouldn't be able to fly much further LOS, it's just to small to see.

100uW = 30.5yds
300uW = 45.3yds
1mW = 185yds
3mW = 254yds
10mW = 334yds

I am currently experiencing some issues with range on my 250 quad. I have a LemonRx satellite Rx (not sure of the model...comes with the Spedix S250). With my Devo 7E set at 150mW, I can only get about 100' from it before signal becomes intermittent and then after a step or two, goes away completely. I JUST flashed the latest Nightly (4-14) in hopes of improving this problem but had no such luck. I currently have the A7105 and the NRF modules installed and they work perfectly. I have also done the "full-range" mod by using a conductive ink pen.

Is there any chance that by doing the 5V power to my stock module I can improve my range? If so, can Cereal_Killer or someone else suggest a switched 5V source to use? I have also been looking as to whether adding an external antenna to the stock module would be of any benefit. I have yet to see anything conclusive. I currently have a "rubber ducky" antenna that I installed for the NRF, so I would be wanting to add another one in the back, hopefully where the empty opening with the rubber cover is in the back.

I'm almost to the point of giving up on the radio and getting something like a Turnigy 9XR or Taranis for my 250. I don't see a point in having an FPV quad racer if I can't get past LOS anyway.

Mine's already buttoned back up but I will mark that pic for you with the source I used on my computer tonight (posting from phone now).

In the mean time I have been thinking about this myself today, in your hardware file did you uncomment the stock module? I didn't (it states it's not needed to uncomment it) but I wondered what happened if I did. I have a very new 7E, maybe something's changed? Can you try that real fast please?

Also can you measure the voltage on your power pin to see what it's running at? If it's already at 5v then this probably won't be the answer to your problem. Also is your lemon in DSMX or DSM2 mode?

Give me a little to mark and reupload that pic for you.

The only thing I did to the hardware IN I with regard to the CYRF was to change the number from 0 to 1. I can't change anything right now, as I have the shield off and am planning to verify that my range mod is working properly. I did the quick test of seeing what the voltage drop was on the battery as I changed Tx power. I didn't get hardly any change in voltage drop.

I'll measure the voltage at the power pin of the module tonight (currently out of town). And my LemonRx receiver is a DSM2 satellite receiver (no DSMx, from what Gary at BuddyRC said).

I now see another guy having the same no range problem with a lemon Rx, I'll never buy another one of them! Even tho there was way more to my issue than just the rx I'll still never buy another, just stick with orange when I need DSMX.

Anyway here's the pic, connect either to the red power pins. I pulled from the closest place- the right side of that large SOT-123 size diode. The orange wire is not switched but the via to the right is, and that's electrically the same as the right side of the diode.

I just redid my range mod and now have significantly greater range, although I really think I should have more. I placed my radio on the ground and walked around with my quad at 10% throttle. I can get to the extents of my property with it cutting out right at the edge. The most distance I'm getting is 170ft, but that is with my 2-story house in the way (not LOS) and with the controller on the ground.

I also measured the voltage at the module at the pin you have your orange wire going to. It's 4.18v. Should I think about doing the 5v wire?

What's the battery voltage when you read that? I think it's probably fine and you won't gain anything by doing what I did here.

Note it's not an actual 5v regulator, I'm simply supplying it battery voltage (minus a few 1/10ths dropped threw a couple diodes).

This is really not the best way at all, it's just what I had to do to get mine working. Ideally you could use a 5v regulator (such as the previously discussed 1117 which comes in many voltages and an adjustable version) so there's some true regulation going on. You could potentially blow your module if you used a 2s LiPO in your tx.


I think most likely I have a bad FET / transistor in mine or maybe a poor factory solder joint / cold weld somewhere (the one that switches the factory module) and all I did with the bodge wire is bypass that for now. Eventually it'd be nice to actually fix it but not right now.

Back to your issue, have you tested resistance between your jumper? Can you post a pic? This thread has some good basic troubleshooting tips for low range after the range mod. Did you use wire or a jumper or a solder blob or what? Also what's your antenna situation for the factory module? Aftermarket installed or what?

Voltage at both of the 5v sources you labeled read 4.61v. The voltage on the display is 4.97v. I use 4 ,AA batteries as my power source.

I haven't tested resistance. Originally I used conductive ink to jump over the resistor. This time, I removed the resistor and bridged the two pads with solder. It's a solid connection now.

I currently have the original antenna laying across the top of the radio case, just below the original antenna's location. It is in a horizontal orientation. The two antennas on my Lemon Rx receiver are in a horizontal plane as well. I am thinking about getting the stuff needed to do an external antenna mod for this module and have it connect through the empty hole in the back of the case.

bugman72 wrote: I am thinking about getting the stuff needed to do an external antenna mod for this module and have it connect through the empty hole in the back of the case.

You in the US? I ordered one a few weeks ago when I added an NRF module and two showed up, tried to send one back but the ebay seller didnt want to pay to get it back so they said keep it. If you want it for just the couple bucks it'll take to ship it to you (CONUS) I'll be more than happy to "pay it forward". PM me your address if you can send a few bucks via paypal and I'll send it out in the morning!


Edit wanted to post this updated image

What happens is the power comes in directly from the battery pack, follows the yellow line threw a large diode providing polarity protection (good design, even with the physical polarity protection provided by the connector) which does drop around .3-.5v (bringing you to your ~4.8Xv you're reading). The power flows up to a P_FET and the via my orange wire goes to. Anything pulled from this line will be powered all the time, it's not switched, if there's a pack plugged in it's drawing from it.
The P-FET switches on/off via the power slider switch so anything on the red drain of it will be switched atleast, tho again NO REGULATION! Other than the low drop over the diode it's pretty much raw batt voltage.

Note the 2 large diodes marked SS14 are providing electrical polarity protection however their main purpose is they (along with the two large TH diodes to their left) make up a half bridge wave rectifier

I am in the US. Do you have the u.FL to SMA extension as well as the rubber ducky antenna? I'll take whatever you have to get rid of. Save me having to wait forever for one. Sending PM with address.

As for the voltage wiring, since I have a 0.5V drop from the spots your marked to the power pin on the CYRF module, would it be worth getting max available voltage to the chip? Or do you think I would even notice enough of a difference to make the mod worthwhile?

Ok first yes I know this is old, almost 6 months old, but today I finally figured out why I only had 2.25v at the devo module. That SOT-123 diode I bypassed with the bodge wire was bad. Poking around inside today I metered it and it was reading .97v so I took it out and tried it on my LCR meter and it either didnt read at all or it read as a resistor. Ended up digging out another SOT-123 diode and putting it back in there and it works perfect now, seeing about 4.8-4.9v at the module and no bodge wire needed!

Just thought I'd update, no idea what killed that diode, it could even have came bad from the factory, hopefully now I might have a little better battery life...

Congrats to figure out your issue
I read this thread several times some weeks ago, hopping to find the issue at my Cyrf module.
Finally I ordered some RDAT212 Power Amplifiers since I think could be my issue. We will see when receive those IC's in a few days...
In the mean time, a nice guy from here sent me an spare 7e Cyrf module and I have range modded and ready to replace mine in case the power amplifier don't repair mine.
BTW, what SOD-123 diode are you talking?
The one you marked in red on his right side (at bottom-right from Cyrf module) on your last attached photo?

Yes that's the one. Good luck with yours.


Video:

Hi Cereal Killer!

How can you measure the drop voltage?
How did you solve it finally? Changing the diode?

It's the problem of this? www.deviationtx.com/forum/6-general-disc...x-range-test-results

Thanks!!

Hi ursus. Initially the fix was supplying regulated 5V directly to the module with a bodge wire. That got me a properly working radio just doing that but eventually I did discover the diode it's self was bad so I replaced it and removed the jumper wire and it's working perfectly still!