Tekin ROC412 knocking noise

[Tekin Prez]

Possible and it would be good to try another motor, but more likely we stop doing some things and turn off some features when there are no sensors. Best guess really is there is a bad solder joint that is humming when power passes thru it. We are doing some things in neutral. This is how we make the chimes at startup also is we vibrate connections on purpose. Perhaps the solder joint is not bad enough to make it fail, but enough to make it hum.

Chances are we are going to want to see it and replace it, but sometimes fun and educational for others to try and debug in public.

[meatmonkey]

If it wasn't for the vid, I would've thought you're joking.

Sorry I can't help, but man, this reads out like my friends calling up from 2,000 miles away and asking me to diagnose their car problem over the phone. Always good for a laugh.

Yet, here is Tekin trying to do just that. Bravo I say.

[ROWDY RACING]

Check the oil.

[dentonmac]

Originally Posted by JohnRobHolmes

Could also be the additional detent force of the roc412 VS the Pro4. By design, it won't be able to start up as smooth and slow as the Pro4 with regular 6 step commutation. Gearing a bit lower would help. Gain some low speed drag, lose some low end control.

Just read this in the World Release forum. And got me thinking about your problem.

With the 18.5 rotor it will have a pretty hefty detent force. At startup/slow speeds it is probably trying to overcome the magnet force created by the larger rotor. Try a smaller pinion and see if the lower ratio helps.

Please keep us updated. Really interested if you can get this thing for an LCC...If it can slow crawl.

[cytogen]

First off, Thanks to Tekin for look into this. I commend the fact that we are able to keep this on the forums for public knowledge and educational purposes. I was expecting a PM to take this off line to reduce the exposure but that was NOT the case. Kudos to Tekin!

With that, I'll continue with the troubleshooting.

Below is a longer vid showing what Tekin has suggested, downgrade the firmware. I'm happy to say this seems to have resolved the issue. However, it has presented a new issue what wasn't present before. During drag brake, my servo glitches and twitches massively.

My servo is a hitec 7954 which is powered from a castle BEC running @ 7.4v output. Only + and - is coming from the BEC to servo and only the signal wire is coming from the RX. The BEC supply wires are soldered directly on the ESC + - poles.

When I bypass the BEC the twitching is gone. I'm having a very hard time trying to determine the relationship of this issue. With the earlier ESC firmware, does it handle the drag brake differently and somehow feedback to the battery (in my case, the BEC too)? or does it not handle it well and causes "interference" to emit from the ESC?

All my steps were documented in the video, just note that at the beginning of the video on the new firmware, there was no servo glutting on drag brake. I know I should of highlighted it a bit more, but you can use the comparison when I had it one the floor trying to get it to knock, the servo never glitches, but after the downgrade, almost every time I release throttle, the servo would glitch as the drag brake engages

It is a longer video as I wanted to do a single shot to keep it authentic. You can fast forward during the upgrade process.



Thanks again for all the help so far!

[cytogen]

dentonmac,

I'm already running a 10 tooth pinion. My intention was to gear it down for better low speed resolution. I was going to go with a 9 tooth but the LHS didn't have any in stock.

[Tekin Prez]

I would like to email you another software version to try. Please email me at jcampbell@teamtekin.com so we can link up.

If I understand your BEC wiring you need to connect the ground from servo to rx. Anytime the white signal wire goes somewhere it needs to have the black wire with it. Since you are not running the seperate BEC to the rx and then to the servo you need the ground to go to both places.

Many times it is a faulty unit, but many time it is also a setup issue, wiring connections, bad servo, bad rx, bad radio or even a battery. We like to debug most thing publicly to help people follow a logical path and figure it out without having to send it in.

[cytogen]

Thanks for all the support!! Email has been sent. I'll update the thread after I have tried it out.

As for the servo wiring, in hindsight, you are correct. Fundamentally I should of ensure everything had a common ground rail to go back to. For the sake of discussion though, what in the code may have changed this behaviour on the servo glitching?

Thanks!

[Tekin Prez]

Lack of a good ground can cause odd and inconsistent problems. On the surface I would say the newer version makes less noise. We are always cleaning things up and improving on each new version as we learn.

I am curious if this issue is still there when you do not use a seperate BEC unit.

Turns out I confused myself and started thinking it was an FxR unit. We do have some new software for the FxR we plan to release soon that we have been beta testing. Unfortunately we do not have any new software for the RS. We are not aware of any problems that needed fixing on the RS. Many, many units running that software for a long time so we know this is not a bug or something. It is likely something specific to your unit or your setup.

After this no seperate bec test it is probably time to just send it in so can look closer at it on the bench.

[cytogen]

In the initial video, you'll notice that the issue was present before the addition of the BEC. So if that was a test you wanted, it's already been done.

So far the older firmware is working as the knocking noise is not there. And if I bypass the BEC and go directly to my RX for the servo then the twitching is gone. I think if got the common ground in there, it should fix the glitching as demonstrated in a few other threads I have read.

Once last thing I'm going to try and do is upgrade it back to the new firmware, remove the setup from the car and see if I can recreate it on the desk. If that is the case, you should be able to do the same on your bench.

[cytogen]

Okay, took the setup out of the rig for a test on the desk. I'm able to replicate it.

Here is the vid of the testing.

[Tekin Prez]

Pretty weird Fortunately our lives are all about finding things that are wrong, figuring them out and fixing them...

It is still possible it is the motor that has a bad sensor board, but not sure why the controller would react this way. Ideally you could try some other BL motor on the bench, but we can do that here if you just want to send both in to us.

Please fill out the service form on website and include it in the package. Put my name on it and use RA# JC55 so it comes to me when it arrives.

[Pabust]

I had no idea it has a "dildo" setup

[ik632]

Kudos to team Tekin for the great support! I can't wait to get my 412 this week.

[losiking1]

Have you tried a different sensor lead?? We have been oval racing Associated B4's with brushless for quite a few years now and sensor leads can cause havoc. If not def spun a rod bearing!! JK. Haven't heard that noise at all before. Best part is Tekin will have you going fo sho.

[cul8tr]

I'm thinking about this system in 3100kv for 1 of my Wraiths.

[nissan_driver24]

I have had this exact same problem on my 17.5 redline motor with a Tekin RS esc. I have changed motor, sensor board, and sensor wire but it never gone away. Never thought of it being a problem cause i'm still running the setup in my G6 ride. I would love to know the fix for it.

[cytogen]

I did try with a different sensor wire, and still has the same results. An interesting note to make, while the motor is knocking, I'll pull the sensor wire off and the noise stops. Plugging the sensor wire back in without powering off the ESC makes the noise stops. So it really seems to be related to the sensor circuitry.

If nissan_driver is having the same issue after replacing motors, it looks to be isolated to the ESC.

[cytogen]

Tekin prez

Thanks for all your attention and support efforts on this matter. I'll be boxing up ESC/Motor combo and shipping it off to you tomorrow. I'm looking forward to the results and hopefully it's just a mere firmware update to fix it.

Thanks!!

[nissan_driver24]

Originally Posted by cytogen

Tekin prez

Thanks for all your attention and support efforts on this matter. I'll be boxing up ESC/Motor combo and shipping it off to you tomorrow. I'm looking forward to the results and hopefully it's just a mere firmware update to fix it.

Thanks!!

Please keep this updated I would love to know the fix to it.