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Asurbakt1

Ninebot One S2 died off after constantly rapid consecutive beeping

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I received my Ninebot One S2 on the 24th of May 2018 (it's been only 20 days so far), and the mileage so far is 318.468 km. The serial number is N2ISD1620T1085. I was extremely enjoying riding it so far, and I was just about to be proficient in riding it with one leg.

But yesterday when I was about to leave home with my ninebot, it strangely failed to work. I turned it on as usual while on the ground, and it did work when I attempted to ride it -- but only for a very brief moment. Out of nowhere afterwards just when I proceeded to ride it forward, the motor began twitching very roughly as if it’s figuring out how to balance, it couldn’t operate smoothly at all (there’s no way I could stand on it in a balanced way). I attempted to ride it to see if it would balance, but it suddenly made constantly rapid consecutive sound of beepings even if it's not lying sideways on the ground. I also heard an unusual ringing sound (like the sound you hear of when you’re having a tinnitus). I turned it off and on again and tried to balance it by lifting it by the handle in carry mode. While in this mode it didn’t make any sound or movement. When I released the handle, it instantly went back to the state where the motor was twitching with that unusual ringing tinnitus-like sound, with the addition of the constantly rapid consecutive beepings – it did that until it died off. Subsequently, I couldn’t turn it on when I press the power button even if I’ve charged it in full, it’s been like that ever since. 

I wasn’t aware of any suspicions sign before it failed other than once a while the motor felt a bit jerkish while I was riding it (but not very often).  What could be the cause of the failure, like has anyone experienced the same thing and how can this be fixed? 

I managed to upload the black box data while on carry mode with the Segway mobile app, and I’ve attached the CSV file in this e-mail -- I have no idea what the numbers mean.

N2OSD1620T1085_BlackData_2018-06-13.csv

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12 minutes ago, Asurbakt1 said:

I received my Ninebot One S2 on the 24th of May 2018 (it's been only 20 days so far), and the mileage so far is 318.468 km. 

the motor began twitching very roughly as if it’s figuring out how to balance, it couldn’t operate smoothly at all (there’s no way I could stand on it in a balanced way). I attempted to ride it to see if it would balance, but it suddenly made constantly rapid consecutive sound of beepings even if it's not lying sideways on the ground. I also heard an unusual ringing sound

Unless you have done something very simple and mechanical like got a stone stuck between the wheel and casing (so does the wheel turn freely with it switched off?). Then surely you do not want to be trying to repair this yourself anyway, it really needs to go back under warrantee if it is that new?

Coming back to turning the wheel with it switched off.

  • If it turns with difficulty and a grating/grinding noise then something stuck in between the tyre and case is possible.
  • If it resists turning like there is a brake on with no noise then that would indicate the main transistors (MOSFET’s) have failed and it will require a new control board.
  • If the wheel turns freely then that would also indicate your symptoms are an electrical failure, just possibly a motor or sensor wire may have come loose and opening it to check for that may be worthwhile (has it had a significant jolt like dropping down a big kerb or higher?)
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It fails to turn on at all now when I press the power button on. The wheel doesn't turn smoothly while it's off when I turn it manually, it turns pretty heavily and roughly like there's something impeding it.

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3 minutes ago, Asurbakt1 said:

It fails to turn on at all now when I press the power button on. The wheel doesn't turn smoothly while it's off when I turn it manually, it turns pretty heavily and roughly like there's something impeding it.

MOSFET failure, there are two or all three motor phases shorted through dead mosfet(s), and that's what "brakes" the motor even while the power is otherwise off. If you disconnect the motor from the mainboard, it should turn without any resistance. You likely need a new mainboard.

Since the wheel is so new, I'd say that should go under warranty.

Edited by esaj
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5 minutes ago, esaj said:

MOSFET failure, there are two or all three motor phases shorted through dead mosfet(s), and that's what "brakes" the motor even while the power is otherwise off. If you disconnect the motor from the mainboard, it should turn without any resistance. You likely need a new mainboard.

 Since the wheel is so new, I'd say that should go under warranty.

I see, wow that's fast, I only had it less than a month. What is the typical cause of a dead mosfet(s)? Sure I've fallen several times while practicing, but I've been riding it fairly carefully.

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9 minutes ago, Asurbakt1 said:

I see, wow that's fast, I only had it less than a month. What is the typical cause of a dead mosfet(s)? Sure I've fallen several times while practicing, but I've been riding it fairly carefully.

There's quite a long list of things that can break them in general, but with the wheels, it seems to be typically overheating. Especially long climbing, as that pushes too much power through them without enough cooling, or sudden jolts of very high power throughput (like hitting a large pothole or such) could be the cause. Some manufacturers have used cheaper, not high enough rated parts... Also, improper electrostatic discharge protection during handling the board can damage them without showing signs immediately (ie. "walking dead"-component, the component's already severely damaged, but continues to work normally for a while).

EDIT: Oh yeah, let's add strong braking in the list, if there are no bypass-diodes next to the mosfets, it might push high currents through the mosfet body reverse diode, heating it a lot. I've known of at least one Ninebot E+ kill its mosfets during braking by this.

Edited by esaj
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48 minutes ago, Asurbakt1 said:

What is the typical cause of a dead mosfet(s)? Sure I've fallen several times while practicing, but I've been riding it fairly carefully.

To add to what @esaj has said - and it’s something we try to drum into people who ride without protection (particularly those who think they are fast and fit enough to run off or roll safely out of it 😂🤣😅) Electronics can fail at any time whether it is a Tesla car or a kitchen timer. 

However, statistically they are most likely to fail in the first month or two then the curve then tails off, but it can seem simply random from then on. For example I had one of the very first portable CD players back in the 80’s, its amplifier failed 3 months ago after running faultlessly for more than 30 years - why should it suddenly fail after all that time?

Mobile components have a hard life, it can be something as simple as a capacitor that has not been secured properly, every time you go over a bump it flexes and eventually the wires break through metal fatigue, or a dry joint in the soldering, or as @esaj said just a poorly handled component with static damage. It doesn’t have to be anything you have done (although the worst thing any EUC rider can do - I assume you haven’t - is ride backwards and forwards on the spot which puts huge amounts of heat into the electronics - there was an idiot on YouTube who “proved” a make of EUC was crap by wiggling back and forth for long periods between two desks until it failed and then blasted the supplier off something rotten when they refused to give him a third replacement.)

I spent a lot of my life as a telephone engineer and then systems trainer. When my students complained bitterly about the reliability of a  phone system I was training them on they soon shut up when I pointed out that those very failures were what earned them their livelihood. If the equipment was perfect they would all be out of work.

In fact reliability, if you looked at the statistics were excellent but all an engineer ever saw was the very few ones that went wrong. No repair engineer ever made a good salesman, to them everything the company sold was crap!

Edited by Keith
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  • Just contact your seller and ask for a new one or repair. Don't bother yourself with such a new wheel.
  • Do NOT ride it again, even if it magically works again.
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