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  1. #1
    RC Enthusiast
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    Unhappy Another Steering Servos Issue Thread

    Hey All,

    New to the forum and relatively new to tinkering with RC cars, although I have been driving them on an off for a long time.

    Bought a TRX-4 Defender a month ago as it was a case of I just gotta have after discovering Traxxas and RTR vehicles. Love it, awesome truck, but it didn't quite scratch the itch for power and speed. Thus I went down the E-revo 2.0 path and picked one up Friday night.

    Spent the evening prepping the truck, charging the batteries and reading the manual ready for some fun in the morning.

    Took the truck out by the apartment block this morning and gave it a blast for 10 mins. What fun. Loved it. Never got past half throttle running dual 3s 5000 mAh Traxxas LiPo's. Then went out for the morning and put the truck in the boot of the car with me. Ran a few errands and then found a nice grassy spot that I could run the truck on and get more of a feeling for it. Was having great fun until all of a sudden, whilst driving very slow and just on grass, the steering locked out with full right lock. I couldn't bring the steering back to neutral or turn left at all. Stopped the car and went over to see what was happening. Couldn't immediately see any issues but could hear the servos working overtime trying to return the steering to a neutral position. I immediately turned the truck off, removed the batteries and put truck back in the car and drove home to inspect further.

    On closer inspection I found that the links adjoining off the left hand servo horn (as you look down on the truck when wheels on the ground) were over extended and locked out forcing the steering arm fully over to the right. Unfortunately rather than just unscrew the servo horn and return it to a normal position I removed the centre screws and bash plate and unlocked the links that way. I then returned the centre screws and bash plates from there. All looked fine until I turned the wheels manually and from the right hand servo (as you look down on the truck when wheels on the ground) made a horrible grinding a clicking noise but only from a neutral steering position to a fully locked right turn. From neutral to left turn there was no sound or grinding noise. Left hand servo felt smooth when turning and no issues at all. Note no power running through the truck and all batteries still removed.

    Next I removed this servo to inspect the gears inside, thinking one of the cogs may have lost teeth or be slipping. On inspection there was no issue.When turning manually all the cogs moved correctly and I couldn't isolate any issues. After returning the servo and re-connecting the horn I could still hear the grinding / clicking like noise when manually moving the steering. Again only from neutral to fully right turn. I decided to power the truck up and see if the wheels would turn. Immediately on powering up both servos were making a lot of noise, just as they were before I powered off the truck after I had the issue. Lots of whirring and generally sounding like they were under stress. Turning the transmitter steering wheel made the servos make different whirring noises, from loud to almost silent, but didn't translate into actual movement of the steering. I then switched the truck off for further inspection.

    I then decided to remove both servo horns so they were not connected to anything and powered the truck up again. Once again the very loud whirring noise coming from both servos and no reaction when turning the steering wheel on the transmitter. Tuning the steering on the transmitted through the small adjustment wheel with the TSM dialled down to zero made the steering servos make different whirring noises but I couldn't see any movement on the horns. Repeated attempts with the steering wheel to see if the horns would move at all ended in no result.

    Powered the truck off and here I am. The servos are clearly getting power, there is, or has been, no smoke emitted from the servo boxes. So I'm assuming they haven't burnt out. There's plenty happening with the gears turning as you can hear the whirring and feel the minute vibrations in the servo housing. The clicking / grinding noise from the right hand servo is still prevalent when manually positioning the wheels with the servo horns reconnected to the steering links. So I've no further idea right now. I did say I was relatively new and I will get in touch with Traxxas Support on Monday but being in Hong Kong that is far away right now so thought I would reach out to the forum for any ideas. Anyone know of what is going on here or experienced the same.

    Lastly, I know that a lot of people have experienced servo issues with the E-revo 2.0 and I think a lot of that boils down to running dual servos for steering. To that end I'm thinking of replacing both servos for a Power HD LW-25MG which looks like it was designed for the TRX-4 but appears to run well in the E-Revo according to a YouTube vid from Kevin Talbot who replaced his steering servos with this after experiencing servo issues with the stock items. Anyone else done this mod or can recommend it? I will speak with Traxxas Support before making this mod though to get their thoughts on my issues first.

    For anyone who's read this far, thank you and sorry for the long post, but, really want to get this truck back out there, if not for me, but for my son. We both loved it for the 20 minutes we had with it and want to spend some more time getting to know it.

    Cheers,
    Delirious.

  2. #2
    RC Champion
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    First and foremost welcome to the forum! The E Revo 2.0 is a great machine once you work through the few little bugs that will come up. Don't get discouraged as we have all been there in one form or another. Couple follow up questions to help get us on track, did you align the servos and ensure they were not fighting each other out of the box? This greatly prevents wear and tear on them from fighting each other when working. Secondly, you said you checked the servo gears...did you open the servo case and take them out and check them or just turn the servo by hand. From the issues your explaining, it honestly sounds like servos are smoked and at least the right one has a partially stripped gear or is missing a tooth or teeth somewhere. Mine lasted me a short bit before out of no where my left servo did almost the same. Mine for sure had lost a couple teeth and it appeared that the teeth bound up the gears at one point causing the right servo to fail as well due to stress in fighting the other servo. Traxxas a lot of times will replace them under warranty, but seeing how many people continue to have issues with these servos...I just moved on.

    I ultimately went to a Savox single servo. Used the Traxxas servo saver for metal geared servos and cut off and cleaned up the left arm off the dual servo arm. I then made a blackout plate to fill the left servo hole in the chassis. Been running that and after finding the sweet spot with it and my driving style with TSM....have had ZERO issues!

    Hope this helps get you on track. I know it doesn't get you running now, but have faith you will be running again soon!
    ABMods 3.3 Revo PE
    Jato 3.3
    Futaba 3PM

  3. #3
    RC Enthusiast
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    Many thanks for the warm welcome and your post back. Much appreciated. In answer to your questions. First of all, unfortunately, no, I didn't check the alignment of the servos prior to running the truck. I just put some fresh batteries in from the get go, did some basic transmitter tests with the truck upside down, and then took her out for play. I guess I was too literal with the RTR term. I will note though, that prior to the original issue of the steering linkage being over extended / fully locked out the servos were not noisy at all and just made the usual noise when turning the transmitter steering wheel. They were almost silent, there was certainly no whirring noise coming from them. In fact the only noise I can remember hearing was the cooling fans on the ESC spinning up.

    Secondly when I dismantled the right hand servo I did look at all the gears immediately under the horn and also turned the steering by hand from the cog that fits into the outer-side steering cog which then itself attaches to the horn. I couldn't see any missing teeth here but I did not remove the gears I just inspected them in situ and turned them from left to right. They also turned smoothly with no grinding. Putting the servo back together again and placing back in the truck the grinding noise and feeling was evident again. Perhaps I will pull it out again and inspect once more. I'm no expert so could have missed something here and it definitely feels like / sounds like something wrong with the gears. Stripped teeth or in-correct positioning of a gear etc.

    Thanks also for your feedback on the Savox replacement. I'm definitely going to be looking at something similar. I think this is a case of less is more here when it comes to servos. One more powerful single servo verses two weaker servos definitely seems to be the way ahead.

    Can't wait to get the E-revo back out for another session. It's a fab truck and never had anything quite like it. For now though at least I have the TRX-4 to scratch that RC itch. It's a long weekend here next weekend so need to get it fixed before then.

    Cheers,
    Delirious.

  4. #4
    RC Competitor
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    Jan 2019
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    New York
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    You'd definitely hear a buzzing noise while the E-Revo sat still if the servos were 'fighting' one another.

    Well, you can follow up with Traxxas and get some replacements, or get something to replace them, the best option being a single stronger servo as mentioned by Rick. Don't have to deal with adjusting two. It's just an easier solution.

    You might as well do both, actually. Folow up with Traxxas, get the replacements from them, sell them, which will offset the price of the replacement you choose.

    Well, it's an option.

    Good luck!

  5. #5
    RC Champion
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    Savox 1231 is what I am running for my single servo set up and Traxxas part # TRA5344x which is the heavy duty servo saver spring you will want. I also added a 3 inch servo extension. Dont absolutely need it as you can make it work without it...but makes life easier in my opinion. Like Devzero said see if Traxxas will replace them, then just sell them new and offset your cost. Fantastic idea.
    ABMods 3.3 Revo PE
    Jato 3.3
    Futaba 3PM

  6. #6
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    Thanks guys. I think I'm going to go with the Power HD LW-25MG which has 25kg-cm and is marginally faster that the original servos. That will be plenty good enough and the stock servo horns fit straight on and it fits right in the servo housing with no mods. Seems a very simple swap out. Also my local hobby store has stock so I can pick up tomorrow.

    I'll then call Traxxas support first thing Monday morning their time to get their view and opinion. If I can get replacement servos as you say I can then sell on or keep as spares.

    Cheers,
    Delirious.

  7. #7
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    Resolution and the E-revo lives to drive another day!

    I stopped by my local hobby store this evening and picked up a Power HD LW-25MG single servo. Installed it this evening removing the old duff servos and hey presto the truck is all good again and now running on a single servo. It feels stronger than the original setup, although hard to really say considering I only had 20 mins with it previously, and is a more simple solution and thus less can go wrong with the setup. You also don't have the scenario of two servos fighting each other.

    As I said in my original post I'm not that experienced with tinkering with things but I managed to do the full job in about 90 minutes. In fact the hardest part was actually just removing the servo cables and plugs from the cable tensioning housing. Trying to wriggle the little plugs out of there took me a good 10 - 15 mins before I cracked it. The rest was pretty simple. Definitely job satisfaction and very pleased I could do it.

    Took it out on completion for a little test drive and runs well. Servo steers sharp and quickly on all surfaces and happy I have the truck to run with again. Now roll-on the weekend.

    One small query for the more experienced folks here. What's the best way to trim the steering? Any tips or tricks to share? The truck runs straight and true but only when I dial in pretty much full trim from the transmitter to the left. Doesn't leave me any further trim to the left should I need. Not a huge problem as I don't race seriously and just mess around with it for fun and it does run straight albeit with maximum trim to the left dialled in. If I can straighten out the steering a little bit so the trim feature on the transmitter is closer to the 12 o'clock position then I will be totally satisfied. Just to confirm that yes I did turn off TSM when playing with the trim and yes I did try to align the servo horn, steering linkage and steering arm all at 90 degrees to each other but maybe this needs tweaking a little? Is that the obvious place to go. I did adjust the little tensioning nut in the linkage to try and get the steering arm as close to 90 degrees as a I could but perhaps I over dialled it in. Is this the obvious place to check and tweak again?

    Lastly, the local hobby store told me they could do a warranty replacement on the old servos for me if I just stop by and drop them off. Great service so I will be doing that and hopefully then have some spares should I have further issues down the line.

    Thanks all for your help,
    Delirious.

  8. #8
    RC Champion
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    That's great to hear! Your confidence will grow leaps and bounds as you work on your truck. As for the new steering servo, you want to set up end points and subtrim this will get it all even for you and prevent the servo from over driving and burning out. Do you have the Bluetooth link add on for your transmitter and the app? If so, it will take you 10 mins tops to get it all dialed in. If not no worries, you can still set it up manually through the transmitter.

    Here is the thread I had for setting it up via the app:
    https://forums.traxxas.com/showthrea...using-link-app

    As for doing it manually, as others stated it is in the manual, you will just need to follow the "tree" to complete doing it.

    Hope this helps and again glad you got her back up and running!
    ABMods 3.3 Revo PE
    Jato 3.3
    Futaba 3PM

  9. #9
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    Thanks for the tips, much appreciated. I don’t have the Bluetooth link for the transmitter but have been thinking about getting one. Here is just the excuse I needed.

    Thanks,
    Delirious.

  10. #10
    RC Qualifier
    Join Date
    Jul 2018
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    Welcome to fourm and 2.0.

    Your trim issue is due to the the alignment of servo at neutral rest position and the horn alignment.

    If I remember right from user manual the horn and linkages are at 7 off. But since you also played with linkages in getting car straight things are now off. to get them back to a zeroed in state here is what I would do.

    Disconnect servo horn from servo.
    Make sure on transmitter trim is at zero.
    Turn car on, so servo can reset itself to a zeroed state
    If wanted make a mark on servo and gear where zeroed state is with marker. This makes getting it close to zeroed with out turning car on again easier
    Move tires so they are centered. ( 1 to 2 toe out is normal, may not of been set correct at factory. )
    Adjust linkages on servo horn untill servo horn drops on to servo gear while servo is at a zeroed state.
    Attach horn screws and test car.

    Online user manual has lots of great info on adjusting toe angle, camber, and many other items. Not sure why a printed one was not included... It's worth a read through. As you will use all items listed in it at some point. Also bookmark the online parts explosion. At least on desktop version. Double clicking on part # pulls up the page to buy the part online from trx. So can make note of # and name to get at LHS and learn names of parts. I also print the diagrams out. For fast reference on the work bench. Wish the parts list was in a faster to find formatting.

    Have fun and enjoy the car.

    Sent from my Pixel 3 XL using Tapatalk

  11. #11
    RC Enthusiast
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    Many thanks, Acidic01. I was actually reading that part of the manual earlier in the week and noticed it states the servo horn is off-set by 7 degrees. I think I set it to close to right angles so at the weekend I will have a play with it and try set it back. As you say lots of info in setting the truck up here with trim, toe, camber etc. I’ll be doing some tweaking at the weekend to get the whole truck back in to a more neutral setting.

    Thanks for the tips also on the exploded diagrams and part numbers. That will definitely come in handy. I’m now just looking forward to getting the truck out and giving it a proper run this weekend.

    Cheers,
    Delirious.

  12. #12
    RC Enthusiast
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    OK. Can properly put this thread to bed now. I tweaked the steering this morning manually by re-positioning the servo horn and then took it out for a quick test drive. It ran true and proper with the remote steering trim knob in the neutral position. So E-Revo 2.0 not only fixed but properly calibrated now.

    In addition I stopped by the local hobby store here in Hong Kong today, and I'm going to give them a shout out for brilliant service, RC Mart, and returned the original faulty servos and they just handed me two brand new ones on the spot there and then. They didn't even test the returned ones until I asked them too; since I'm relatively new to tinkering and I wanted to confirm what I thought to be correct by someone more experienced than me. Anyway testing confirmed both dead servos.

    I really wasn't expecting them to give me two new servos straight away. I thought they would send to Traxxas themselves and file the warranty claim for me. They just tossed my old ones in the bin and gave me the new ones

    Oh and whilst I was there I managed to pick a 1/16th E-Revo VXL for my son. The circle is now complete. Totally fixed E-Revo 2.0, spare servos should I need for the future and one very very happy son. Great service all round and thanks for everyone's help here.

    Cheers,
    Delirious.

  13. #13
    RC Qualifier
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    Ad you got the 2.0 going. The Merv is a blast.

    Sent from my Pixel 3 XL using Tapatalk

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