strange issue possibly servo?

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droopy

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so I've posted this on a few other sites, hoping to get some insight as to what exactly is going on with my aftershock. thought maybe someone here had gone through similar issues.

hey, I'm kind of new to this forum, been out of rc for a very long time, but just got back into it after some time off from motocross racing.

i have a very strange issue with a losi aftershock i picked up used and poorly set up. I've gone through it and it runs great now and was driving fine with a salvaged old tamiya am TxRx with a busted antenna. everything worked fine, but if i got more than 5 feet away from it, it would glitch insanely. this receiver was put in by the previous owner who said it had a problem with the JR receiver set it had been using where it would glitch out and randomly lock the steering hard to the left and stop working.

out of curiosity, i hooked up the old JR system and it did exactly as described. since then i have put a few other TxRx combos in it with strange results. some wont work at all even though they were working fine in other models, and the last one was the TxRx from my old rustler. i put everything in and it seemed to cure all my issues. took it out to do some tuning, and all of a sudden it starts doing the exact same thing again, but with a new twist to it that makes it dangerous to drive. once the steering goes full lock left, it then waits a moment, and slams the throttle wide open. luckily it did a backflip and landed in the ditch upside down.

this receiver and transmitter was working flawlessly in my rustler for the last few months. i havent put the Tamiya receiver back in yet, as the range issues are as big of a concern as these other problems.

i have a spectrum dx3 for my 1/8 scale truggy that i am trying to find a spare receiver for so i can use that in the losi, but i have a worry that there may be something else going on here. is there any way that a bad servo could possibly cause issues with the reciever and be causing the wide open throttle issue?

anyways, sorry for the long post, and thanks for any help you guys might be able to provide me with.
 
Well, thats a tough one...Its doubtful that its teh TX/RX since you wouldnt be having the same problem with multiple radios, especially a known good radio. I've seen bad servos do some funky things but its never affected anything but the servo that was bad. That being said I'm not saying its not possible I've just never seen it. Only thing I can think of is maybe you have a wire somewhere thats shorting out or maybe your RX pack needs charged. I know that last one is a long shot but if your RX pack isnt charging up fully then maybe that could cause some issue...I'm grabbing at straws on this one.
 
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so am i. at this point I'm considering ordering all new servos and a new spectrum receiver just to see what the hell is going on, but at the same time, money is tight and i might have to shelf this thing for awhile. thanks for the reply. if anyone else has any ideas or suggestions, i am all ears.
 
were all of the radios you tried FM like the original JR one? I mean except for the AM one with the broken antenna? It almost sounds like maybe something is interfering with the radio signal...
 
i was thinking that too but it does happen everywhere i take the truck too. also, the original JR radio was also AM. it was the xr2i. i wish there was somewhere local that i could pick up a spektrum receiver to put in this thing just to be sure. i dont really want to take the receiver out of my HPI just for the added down time. decisions decisions.....
 
Could just pick up a cheap Flysky GT3B...its only $40 w/RX and its not a bad little 2.4GHz radio. just a thought.
 
i was actually looking at the radiolink rc3s today.... i can get that for about $50 canadian shipped, and so far the best i can do for a spektrum receiver on fleabay has been about $40-45 shipped...... starting to look like and option, but it still is stumping me how these radio systems are all doing the same thing except one that has no range and one that works fine for 5 minutes then goes right into the same pattern,. i thought maybe the receiver was overheating, but I'm not sure how hot one should get. its 77 degrees F at its worst. that doesn't seem high to me.
 
You could try just one servo at a time and see if when you plug in one or the other the issue happens. you can also try each servo in the steering channel, and then both in the throttle channel ( one at a time of course lol) That would at least help narrow it down for you.
 
You could try just one servo at a time and see if when you plug in one or the other the issue happens. you can also try each servo in the steering channel, and then both in the throttle channel ( one at a time of course lol) That would at least help narrow it down for you.
Yeah...its almost got to be a servo...this is a good idea.
 
i agree that this is the way to go for now, this was going to be my plan for today if i get some extra time to work on the truck a bit. ill let you guys know what i find out.
 
i agree that this is the way to go for now, this was going to be my plan for today if i get some extra time to work on the truck a bit. ill let you guys know what i find out.
Please do I'm very curious to find out if it's a servo or not
 
If it only does it while its driving I know the problem but if it does it sitting still as well its a servo my xxl did that and it was locking on a bad steer pivot point changed and never had the problem again
 
it does do it while just sitting as well, usually when i bench test it, i can turn the wheels full chock either direction, and if i hold it for about 30 seconds, it will then either stay locked to the left, or turn left and stay locked to the left, followed by the throttle then going wide open a second or two later. I'm going to try and check each servo individually for the steering later today. i dont think it will be the throttle servo that is the issue, as i can play with the throttle all i want for as long as i want, as long as i dont touch the steering. once i start trying to steer, its game over very quickly. at this point I'm pretty confidant that this will turn out to be a steering servo issue, but it just seems so unlikely that it will cause the throttle to go wide open because of it. thanks for all the suggestions so far guys, and i will make sure to update this everytime i get some info or a possible fix. of all the places I've posted this, you guys have been the most helpful.
 
ok, so i think it is one steering servo causing the issue. went one at a time after i got teh issue to happen repeatably, and with one servo unhooked, it still twitched but a lot less, but most importantly, the throttle servo was still twitching, but not going wide open. hooked that one back up and unhooked the other one, no more throttle twitch at all, no more steering twitch at all. still makes no sense to me at all, but it seems to be the problem. I'm ordering some new servos, so it will be a while before i know 100% positively but i think this is it. i also hooked the original JR radio back up with the one steering servo, still no issues. so far...... lol ill update when i get the new servos in.
 
It must be throwing some sort of feedback into the RX that is interfering with the other servos too.
 
all i know for sure is that its killing me waiting for parts to show up. that, and its pretty scary how out of control this thing goes over one bad servo. last time i tried it out, i was a few feet from having to pay for damages on a neighbors car.
 
i was looking a those the other day. seems like a wise investment
 
so, i did some more tinkering and just general double checking of connections, and while i do feel that one steering servo is not 100% and will be replacing both of them anyways, i think a few bad connections and lowish voltage in my receiver pack amplified the issue greatly. i did some more testing and have only been taking it to places where there is no one around to possibly be injured if this thing goes nuts again, but it is working now. its a blast and I'm back to tuning again so when the new servos come in it should be in great shape. i do love the sound and smell of nitro much more than i ever enjoyed electric.
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