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Thread: Tekin RX8 problem..

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Old 11-22-2010, 11:50 AM   #1
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Lightbulb Tekin RX8 problem..

I was going to post this elsewhere but figured this would be the best place..

What I currently have.. Hyper 10SC, the esc is a Tekin RX8 with an SC4X 5.5 motor (16t pinion), along with two ThunderPower 25c 5100mah lipos, a Futaba 3PM 2.4 transmitter and a Futaba R603FF receiver. There is no timing done on the motor or via software, everything in hotwire is basically default with the exception I changed the voltage cutoff, currently using vegas 212.

The current problem.. I can run for about 2 minutes (about 1600-2000mah worth) before the truck will start having problems, can pull the throttle and it won't go, or is sporatic comes and goes. On the RX8 I see 3 lights flashing, 5 6 7.. according to the manual "Radio signal found but higher than expected", this happens repeatedly back to back.

I have tried running batteries back to back, when it happens I'll quickly swap the battery out and continue running and the truck will be fine again for a few minutes. I've tried using a 40c 5000mah pack and the same issue occurs, and it does the same between 3 different lipo packs.

Also tried a different futaba transmitter, then tried a different receiver, also tried a new sensor cable, running without a sensor cable, etc... I have recalibrated the esc a dozen times, cleared my transmitter model, reset it all to defaults, factory reset it, etc.

The motor temp isnt even 100, the rx8 is at 1 bar for temp (and isn't hot) so I know it isnt overheating, also none of the wires are warm.

Prior to this I had a Redline 6.5 that overheated while using the rx8 (I don't know if this would cause it), it was replaced with an sc4x 5.5, the first few weekends I had no issues, only yesterday did this problem start, it happened a couple times, I assumed it was the voltage cutoff, but after today noticed the 5 6 7 led's flashing indicating it was in fact not the cutoff causing this.


Sooo... does anyone have any information on this issue, might know how to fix it, or is it at a point where the rx8 just has to be sent in for repair? I've tried everything I can think of aside from getting a new rx8 and trying it.

Any help or suggestions on this issue would be appreciated.
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Old 11-23-2010, 01:20 AM   #2
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Have you tried adjusting the throttle center on the radio I know I have had the same problem and when I found the actual neutral on the ESC it has worked just fine. Try adjusting that and see if it helps. HTH
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Old 11-24-2010, 06:30 AM   #3
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make sure your wires are hooked up A B C .
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Old 11-27-2010, 11:05 AM   #4
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Quote:
Originally Posted by CRAZYACE63 View Post
Have you tried adjusting the throttle center on the radio I know I have had the same problem and when I found the actual neutral on the ESC it has worked just fine. Try adjusting that and see if it helps. HTH
I tried that among trying 2 other transmitters and receivers all together, both confirmed working on other hypers.

Quote:
Originally Posted by Redron123 View Post
make sure your wires are hooked up A B C .
They are hooked up right... if they weren't the truck wouldn't run at all lol.


Thanks for the suggestions, however the problem has vanished out of the blue, I never found what caused it. Was testing one day to see if I could figure out the problem and after the 4th run it didn't do it again, and I couldn't replicate it.

I'm just glad it's gone for now, hopefully it doesn't return.
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Old 11-29-2010, 12:49 AM   #5
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Well at least it is gone for now. But def. keep an eye on that thing and the first sign of trouble I would have it back to Tekin.
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Old 11-29-2010, 01:46 AM   #6
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Originally Posted by CRAZYACE63 View Post
Well at least it is gone for now. But def. keep an eye on that thing and the first sign of trouble I would have it back to Tekin.
Ran all day Sunday without an issue, still no idea what caused it.

Will have a spare rx8 soon just in case this one does decide to bite the dust, will probably end up sending it in to tekin anyways, wouldn't mind having it checked out in general, see if there's anything wrong with it.
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Old 11-29-2010, 04:03 AM   #7
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A low C rating on the battery won't help, but it sounds like the battery wasn't fully charged and it hit the cut-off on the esc. It will studder, and then recover, and studder again. Just double check your cut-off and make sure the batteries are balanced and fully charged. A bad balance can do the same thing and the charger will say they are charged when they are not.
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Old 11-29-2010, 08:12 AM   #8
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A low C rating on the battery won't help, but it sounds like the battery wasn't fully charged and it hit the cut-off on the esc. It will studder, and then recover, and studder again. Just double check your cut-off and make sure the batteries are balanced and fully charged. A bad balance can do the same thing and the charger will say they are charged when they are not.
So 40c is a low rating? The batteries are always balanced, monitored through software and show correct voltages. Also, the cutoff would have led's 135, not 567, which indicate a different problem. It also did it with 3+ different lipo packs that work in other hypers with the same setup, only did it on mine.
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Old 11-29-2010, 09:25 AM   #9
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Here's why I stated the battery... Per the manual, lights 5,6,7 are radio signal not found, which you don't have, so the things I know that will cause what you describe are;

Bad solder joint
Battery at cut off limit
Bad sensor wire
Bad capacitor

If you like pm me and I will give you my number, but check those items minus the battery at the cut off limit and the sensor wire. I suspect its a bad wire or connection at this point.

I did think of one more item, if its not any of those and not a receiver wire, dirt on the receiver.

Last edited by Dragula; 11-29-2010 at 10:47 AM.
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Old 11-29-2010, 11:31 AM   #10
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No offense, but I've tried 6 different batteries, all of them work in other hypers with no issues, from 25c to 40c. Typically I can get a runtime of 6-7 minutes, however I was only getting a minute or two.

Per the manual, 567 means the radio signal was found, but was higher than expected so it cuts off. This is the part that made no sense.

And as I said, I tried another transmitter/receiver both confirmed working on other hypers, didn't work on mine, put them back on another hyper and they work fine, so we know it's something to do with mine. I also took apart my receiver just in case but found no dirt, I however do tape the holes up so it's not easy for dirt to get in.

I'm not sure if the rx8 has a capacitor, or is it inside the case? As for sensor wire, I tried 2 brand new ones along with running without one.

I also tried completely taking the voltage cutoff out by lowing it to like 3v. Now, the solder joints I'm not sure on, however all of the joints have good solder, none budge and look solid and appear to have no fractures.

I appreciate the help, but at this point I've exhausted pretty much every option except for swapping out the rx8 for a different one, and the problem vanished before I could do that. Soooo... heres to hoping the problem doesn't return. :)
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