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(solved) Spectrum 2.4 GHZ issue

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Hi. I was switching my radiogear for a nice Ko Propo EX-1 Mars. Works like a charme with FM40 and somehow I got my hands on a Spectrum 2.4ghz module extra incl. four receivers (SR210).

I tried to get it run but now its like the signal is very glitchy. I tested several ESC in combinations with old servos and brand new ones (coreless/brushless) and its absolutely not possible to run it like this. Firts I mentioned the older low tech servos do work and the new ones not really (they stutter).

Until I tired a TEU-101 with extra BEC line. This is stable with all servos and throttle is precise. How can it be? I run 2S LiPo and they are charged at least to storagevoltage. The receiver need a min. voltage of 3.5V.

Any idears? I am new to GHZ band.

 

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I use the newer Spektrum gear, but my understanding from reading older complaints on forums is that the older Spektrum products were glitchy and required Glitch Busters or external BEC's.

 

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Glitch buster did not help. It really looks like servo drains too much voltage. :(

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I put the servo direct to the LiPo and glitches are gone. Great that the new servo takes 7.4V : )

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On 1/5/2021 at 9:51 AM, Collin said:

I put the servo direct to the LiPo and glitches are gone. Great that the new servo takes 7.4V : )

You should be able to use external BEC's where your servos can't take 7.4V (or spend the money on ESC's that have at least 5 amps for it's internal BEC).

 

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6 hours ago, Mahjik said:

You should be able to use external BEC's where your servos can't take 7.4V (or spend the money on ESC's that have at least 5 amps for it's internal BEC).

 

Direct voltage to servo did work,... but not : ( When pulling the throtlle some signals going to steer the servo to the left. No fun.

Check the video: https://a-tom.org/tc/DS_glitch.mov

Any idears? Is it only the external BEC what can solve this problem?

AS you can see I am using end 90s high end ESCs which did not had BEC. Swaping ESC is no option for me.

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Well, you did mention that everything worked fine when you tested "Until I tired a TEU-101 with extra BEC line. This is stable with all servos and throttle is precise."  There is a reason most modern ESC's have internal BEC's.  

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Looks like you have an LRP Indy ESC.  They have BEC.  The clue here is that the TEU101 did not show the issue, this is because that ESC does NOT have a BEC circuit, it simply passes the main battery voltage straight to the receiver.  The problem is being caused by the ESC's internal BEC circuit output voltage dipping when the ESC is under high load, causing a momentary brownout of the receiver and consequent uncontrolled servo behaviour.  The solutions available - put a capacitor (like a glitch buster, not sure how big a capacitor you have tried already) in a spare receiver channel across the +/- terminals, use an external BEC unit, or lastly, run the servo straight off the main battery voltage.

There were a couple of the older Spektrum receivers that were sensitive to this.  I have had the problem before, also lost laps from a transponder that browned out due to losing power caused by the same thing.

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22 hours ago, LongRat said:

Looks like you have an LRP Indy ESC.  They have BEC.  The clue here is that the TEU101 did not show the issue, this is because that ESC does NOT have a BEC circuit, it simply passes the main battery voltage straight to the receiver.  The problem is being caused by the ESC's internal BEC circuit output voltage dipping when the ESC is under high load, causing a momentary brownout of the receiver and consequent uncontrolled servo behaviour.  The solutions available - put a capacitor (like a glitch buster, not sure how big a capacitor you have tried already) in a spare receiver channel across the +/- terminals, use an external BEC unit, or lastly, run the servo straight off the main battery voltage.

There were a couple of the older Spektrum receivers that were sensitive to this.  I have had the problem before, also lost laps from a transponder that browned out due to losing power caused by the same thing.

Hi LongRat. Ok, lot of very good informations. Seem like I have various brownout sources. Motor and servo.

Right now (on the video linked above) steering servo is on permanent power (7.4V). The servo direct to the receiver made the motor spin when the green LED on the receiver (SR201) went out. Steering hard left/right drain too much voltage and reicever shut down. This is solved by pernanet voltage source.

Brownout by throttle. I can not spot any difference on the green LED when accellerate hard which cause this steering servo issue.But as you saied I am also pretty shure its the motor voltage peak which influece the steering servo. Just tried a 2200uf to the +/- of the receiver but nothing changed. I read others recommend 4000uf which I dont have at home. maybe I find some others just to add on for a try.

Seems like I need a external BEC. I wanted to avoid loading tons of electronic on my Dyna Storm but my new Ko Propo Mars and the 2.4ghz module is simply soo cool hat I dont care anymore. It just need to work perfect at the end.

P.S.: Put the other Spectrum receiver in both other Dyna Storm and Blaster which run brushless (LRP & Nosram). No glitches, no steering issue, all perfect running via internal BEC. Seems like its the old scool high end electrics which is pretty dodgy.


 

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23 hours ago, Mahjik said:

Well, you did mention that everything worked fine when you tested "Until I tired a TEU-101 with extra BEC line. This is stable with all servos and throttle is precise."  There is a reason most modern ESC's have internal BEC's.  

Yep, kind of because my test setup was with a silver can. The hot no limit ESC with 13x2T motor drains much more amps. And LongRat explained, its onle battery voltage lead trough the TEU101.

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@LongRat Hi. I couldt solve the glitches.

Servo is permanent to the LiPo with its 7,4V.
The spektrum receiver on 5V/5A UBEC direct to LiPo.

Adding 2200uF Glitch Buster capacitor does not solve it.

The internal BEC from the ESC coming, it makes no difference if I cut the red (+) to the receiver or not.

Swaped the 2.4 Ghz to the 40fm and no glitches : (

Any suggestions?

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The only thing that makes sense to me is, you are usinf analog servos (as mentioned old servos) with a digital radio.

 

does it anywhere on the servo say Digital?

I tried a AM 27mhz radio with digital servo and got the same result.

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59 minutes ago, Collin said:

@LongRat Hi. I couldt solve the glitches.

Servo is permanent to the LiPo with its 7,4V.
The spektrum receiver on 5V/5A UBEC direct to LiPo.

Adding 2200uF Glitch Buster capacitor does not solve it.

The internal BEC from the ESC coming, it makes no difference if I cut the red (+) to the receiver or not.

Swaped the 2.4 Ghz to the 40fm and no glitches : (

Any suggestions?

You just answerd yourself.

 

it works fine with a analog radio but on the spektr not. 
 

so get digital servos and done.

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The newer Spektrum receivers apparently address the issues around the glitches based around power (so the SR215 as compared to the SR210).  IMO, your issue with likely more with the ESC's you are pairing with it.  You have to see what the internal BEC is off the ESC and then see what type of drain you getting from your servo.  For example, some Savox servos are known to pull almost 5 amps.  If the ESC has an internal BEC of 1.5 or 3 amps, the servo is going to overload the internal BEC and cause issues with the receiver as well.

 

Without knowing the exact ESC's you are testing with, it seems you either need to use ESC's with decent internal BEC's or use an ESC with no internal BEC with an external BEC inline.  It might help to list the ESC's you are trying to use for others to assist but I've had no issues with my Spektrum gear using Tekin ESC's but they have a 5A internal BEC.  They are expensive but I picked them specifically to avoid any glitch situations.

 

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Ok, back to start line.

ESC is a LRP INDY 600, Motor Corally 12x2T, UBEV 5V/5amp. Glitch Buster 2200uf, Servo SRT CH6012 Coreless Servo HV.

INTERNAL ESC BEC current: 1.6A max (30sec), 0.6A(cont.)

 

SETUP 1)
LiPo full charged. ONLY ESC to the RX (receiver), no steering, no UBEC, no capacitor. I can give gas in various pattern, full, half, low, punching the trigger fast, the GREEN LED on the receiver stays green, no brownout so far. Seems like motor and internal BEC is fine.

SETUP 2)
LiPo still full, ONLY steering servo to the RX, no UBEC, no capacitor. When turning steering once to left/right the GREEN LED goes off pretty soon. Adding 2200uf cap makes it a bit better but not. Adding UBEC a lot better but not really fix it completely.

Now I soldered the cap directly to the 5V out of the UBEC and this seems to work right now. When I turn steering hard left/right the receiver stays on. Cap could be bigger and UBEC more powerfull. Connecting servo direct to the LIPo is best result for steering.

Measuring voltage drop at the UBEC out to servo from 5V idle down to under 1V when hard steering left/right.

But what is still glitching, the steering wants to turn right for a split second when throttle up. To mention, this are glitches, no brownouts.
Motor has three lttle caps solderd between +/-/shield.

How can I eleminate this glitch? do I have to split the circiuts somehow? Can I do so? Shall I get a 10amp UBEC?
 

 

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@Mahjik Thanks for your input. Checked the SCR manual and it says what you mentioned, the intenal BEC is to weak. Now I am not shure if even my 5V/5amp UBEC is hot enough...

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If your UBEC output voltage is sagging to under 1V under servo load, that is really bad.  You tried a different servo?  I can't imagine you would need over 5A unless the servo has a fault.

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Just wanted the edit my previous post. I did tried two old noname servos, analog ones I guess. Have not measured the voltage drop yet but this throttle-to-steering glitch is happening too.

Now I seperated the circiuts. +/_ from ESC internal BEC are unplugged and the glitch is gone. But Throttle sensitivity got lost, at least it feels like...

UPDATE:
The other noname servo did not show any voltage drop.

About splitting the BEC circiuts. When I just go with the signal (white) from ESC to RX, the glitching in steering is very low. But the throttle is not working propperly anymore. Added - (black) and throttle was very sensitiv as it should be, but the steering was gllitching again.

So what is the issue now? The motor/ESC generates a signal which forces the steering to turn full left. Are this still brownouts? I am confued.

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Can you open the reciever and look for solder joints that have like a white cloud over them or solder that melted with other joints?

happend to Me on a charger, scraping off the excess solder helped. Is the antenna maybe damged?

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5 hours ago, Fabia130vRS said:

Can you open the reciever and look for solder joints that have like a white cloud over them or solder that melted with other joints?

happend to Me on a charger, scraping off the excess solder helped. Is the antenna maybe damged?

I have four of this Spektrum SR200 and all are new and doing the same issue with this combination of electronics.

Shure, I could just put a brushless combo in, since this is working with two other models, but this ESC/Motor combo I want to keep on my buggy.

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You need the (-) wire from ESC to RX or the signal will have no ground.  However just thinking this through, doing this might create a 'ground loop' between RX, UBEC and ESC.  Many external BECs have ferrite rings on them - has yours?  This is to suppress voltage spikes caused by rapid changes in current.

Here's one of my Turnigy UBEC units with a ferrite ring as supplied.

 

IMG_20210201_211948027.jpg

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Its basicly the same UBEC as I have and it has the ferrit ring as well. Okay, if (-/black) from ESC coming is needed, there is also the glitch coming from.

Maybe trying another ESC? Also I think its not possible to run two seperate circius, as the RX will always connect them. :huh:

 

Update 1: Tried another ESC and motor and still glitches. In all combinations.

Update 2: Now I got brownouts on RX. :blink: Did not changed anything, still Servo direct to LiPo, RX with UBEC. Seems like the behaviour changes several times a day. Its crazy.


 

 

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I haven't use a SR210 before..  I do have some of the older SR2000's that are in use with brushless/Lipo setups.  However, as mentioned my ESC's have a 5A internal BEC.  I also have some of the newer receivers SR215's which Spektrum have mentioned address some of the older issues of glitching.  Having said that, I think the main two options are using an ESC with a higher rated internal BEC or trying their newer receivers.  The newer receivers are relatively cheap so it wouldn't cost a lot to try one out.  As for the ESC, unless you are running Savox servos, I don't think you'll need 5A for the internal BEC.  3A should work.

Personally, if possible, I would try on of their new receivers.  They remove the hassle of keeping a bind plug around.

 

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