KS16 wont turn on

[David S]

I was riding my wheel and walked in to a store and was unable to power it off. the lights stayed on but would not allow me to switch it off, it also wasn't on as it wasnt reacting to leaning. a few minutes later the motor turned on for a second but then the wheel shut completely off. everything is off now and it won't turn on. Also I wasn't even able to tow it as something seemed to be resisting being pushed. Anyone know a solution to this?

[Cloud]

Your control board is fried. Put your nose to the wheel, is there a burning/ chemical smell? Get the control board replaced.

[David S]

I opened it up and looked around. I didn't smell anything burning but it had time to cool down before i opened it up.

[Cloud]

Can you smell right at the control board, particularly the mosfets? Even if you dont smell burning, i still believe its your control board that needs replacement

Edited August 13, 2016 by Cloud

[Chriull]

If the wheel resists turning while turnec off, normally the mosfets are fried.

if you want to secure the diagnosis you could remove the fuse/power plug at the mainboard to be sure the wheel is turned off. If then there is still the resistance of the wheel you can as last step unplug the motor from the mainboard. If then the wheel turns free again it's a short by dead mosfets.

[OliverH]

Can you measure voltage on the power connectors of the PCB? If you unplug the power switch on the PCB and you check in resistance mode with your volt-resistance checker if the switch works as desired? 

Maybe someone can post which voltage has to been on which point to go through a checklist to locate the problem.

[Håvard Hamran]

The exact thing happened to me. I've had my KS16 for close to two weeks now. I went out riding for a few hours, and luckily(!) I had just stopped when this occurred. The unit was powered and lights on, but suddenly no gyro reaction. I tried button combinations with long presses, but to no result. I could not turn it off. After a couple of minutes, the motor kicked hard three times on its own without me doing anything, and finally blew the fuse on the third time due to overcurrent. 

I just picked my unit not 30 minutes ago up at the Norwegian distributor Airwheel Norge in Drammen, and the technician there said there was no damage to the motherboard, only a blown fuse. In dialogue with Kingsong he hadn't replaced the motherboard, only the fuse. However as has been pointed out in other threads as a weakness to the Rev. 1.2 board, he also shortened, reinforced and resoldered the capacitor legs, to avoid them breaking. As this had been observed as a weakness in these units in other threads on the forum.

A couple of days ago, another forum user from Norway, @Frode, had a bad faceplant on his new unit,  presumably due to this fault. The big resistor on the board also blew in his case. I believe he got his whole motherboard replaced and upgraded to Rev 1.3. 

This is one of the problems with only having a momentary on switch, without having a main latching power switch in backup to kill the unit if the firmware glitches. 

Still, the KS16 is an amazing EUC, and after trying the Gotway MCM4 ACM, Ninebot P, and a few other models, the KS16 definitely stood out as a favorite. 

[Frode]

4 hours ago, Håvard Hamran said:

had a bad faceplant -

Nyeahhh, not that bad. I was lucky - and apparently have a hard skull, strong teeth and strong wrists. My nose and lips went sore, blue and big. My left knee still hurts, but that is because I have since fallen 3 times more on the same knee (what is it about that knee?), one time running the wheel into a small pit filled with loose sand (but my knee hit harder ground ), the second time I stumbled while walking along a pond fishing for big trout (I've never thought about using knee-pads while fishing ) and the third time my feet slipped on the pedals while exercising several tight turns in a row (this time I luckily had my knee-pads on ).

4 hours ago, Håvard Hamran said:

I believe he got his whole motherboard replaced and upgraded to Rev 1.3. 

Yes, this is true.

 

4 hours ago, Håvard Hamran said:

the KS16 is an amazing EUC

Agree!

[David S]

Harvard the way you described what happened to you sounds exactly like mine. Opening up the wheel causes a liltle anxiety for me as i'm not really good at all that stuff. I was able to open it up to change a tire tube a few weeks ago, I'm assuming to access everything else i need to open it up more than that?

[Chris]

What firmware versions are you guys with problems running?

[David S]

I was on 1.21 when it happened. Jason shipped me a new control board and its working again now, I upgraded to 1.22 after

[Jason McNeil]

36 minutes ago, David S said:

I was on 1.21 when it happened. Jason shipped me a new control board and its working again now, I upgraded to 1.22 after

Here are some statistics about this problem from our experience: 

• Out of about 100 KS 16"s we've sold so far, in 4 consignments, 3 boards have been affected by this fault
• There are no signs of physical damage on the board, like burnt resistors, fuses, MOSFETS 
• Aux seems to function, so this rules out power input causes
• Wheel  spins freely, probably not MOSFET damage
• In one case, board died within the first hour, rest were in the after a month or more of use

I'm sending these back to KS for analysis/fault-identification. If anyone else has had KS board failures, please report it here. It might help track what, if any, commonality.

[Blunzn]

had the power-off problem too some days ago with my KS16 840WH. made a small shopping trip. no problem at the first shop but at the second one ... I went inside and couldn't switch it off. i tried to press the on/off button a few times for different durations, but nothing helped. a bit confused I leaned it against a wall and continued to shop. after paying it suddenly worked again, like nothing happened.

no blown fuse or other problems since then ... except a crash, which was totaly unrelated, through overspeeding. but thats a different story  

i should have a motherboard from the first few batches not sure which version. Firmware is the latest 1.22

[HEC]

2 hours ago, Blunzn said:

had the power-off problem too some days ago with my KS16 840WH. made a small shopping trip. no problem at the first shop but at the second one ... I went inside and couldn't switch it off. i tried to press the on/off button a few times for different durations, but nothing helped. a bit confused I leaned it against a wall and continued to shop. after paying it suddenly worked again, like nothing happened.

no blown fuse or other problems since then ... except a crash, which was totaly unrelated, through overspeeding. but thats a different story  

i should have a motherboard from the first few batches not sure which version. Firmware is the latest 1.22

Have exactly the same issue yesterday after long leisure ride, FW v1.22 ... Got home, stepped off the wheel at the crossing in front of my house waiting for the green light and then pushed the powered on wheel to the lobby as hundred times before. Tried to turn it off so I can carry it up the stairs but the wheel remained semi-turned on with the front light and side LEDs still on though it was not balancing anymore. The battery was at "3 yellow LEDs", fully charged before a long ride. After short moment I've tried to connect the v1.4 KS app to check the wheel's status but it was unable to see the wheel. Then I've tried the WheelLog from @JumpMaster and it has connected but all values were zero. Shortly after that wheel finally turned off completely though I'm unsure if it was due use of either of the apps or simply after certain period of time passed since pushing the power button. I grabbed the wheel and carried it upstairs first prior any further "investigation". Then I've tested the wheel and it was behaving again including talking to both apps, the reported temperature was 40 degrees. I've left it to cool down a bit and then recharged it and rode it the same day at the evening on another long ride without any issues.

Edited September 11, 2016 by HEC

[Blunzn]

yep, the "not balancing" and "leds still on" was the same with mine.

[RenaissanceMan]

 

On 13.8.2016 at 2:21 AM, David S said:

I was riding my wheel and walked in to a store and was unable to power it off. the lights stayed on but would not allow me to switch it off, it also wasn't on as it wasnt reacting to leaning. a few minutes later the motor turned on for a second but then the wheel shut completely off. everything is off now and it won't turn on. Also I wasn't even able to tow it as something seemed to be resisting being pushed. Anyone know a solution to this?

@David S

I had a similar problem:

I suspect the wheel got confused by conflicting bluetooth messages from several apps that were talking to the wheel simultaneously. Did you have multiple apps running while this happened?

Edited September 12, 2016 by RenaissanceMan
added "multiple"

[JumpMaster]

3 minutes ago, RenaissanceMan said:

I suspect the wheel got confused by conflicting bluetooth messages from several apps that were talking to the wheel simultaneously. Did you have apps running while this happened?

 

I don't it's possible for this to be the cause of any issue.  The parts of the circuit board controlling the wheel are not going to be confused by anything happening with the bluetooth modules.  The bluetooth module is used to broadcast data and take in commands.  Unless one of those command is "play dead" using many apps from many phones will not break the wheel.  If the wheel can connect to 1, or 2, or 100, apps/phones at the same time it's because the bluetooth chip was designed too.

I really don't want anyone becoming unnecessarily scared of using WheelLog or the official Kingsong app.

[HEC]

6 minutes ago, JumpMaster said:

I really don't want anyone becoming unnecessarily scared of using WheelLog or the official Kingsong app.

While I agree that it should be technically impossible to damage the wheel by BT app I believe the @RenaissanceMan's main concern is usage of the multiply apps at the same time. While wheel should be able to withstand that without any issues as it already allows multiply apps to connect in theory incorrect programing / bugs in firmware might at worse lead to some unexpected results or behaviour though those should be only temporary without permanent effect and be resolved by power cycling the wheel.

To add to my above post - the issue happened after the ride during which I've not used any apps or BT connection at all so it's definitely not related to app communication.

[RenaissanceMan]

9 minutes ago, JumpMaster said:

 

I don't it's possible for this to be the cause of any issue.  The parts of the circuit board controlling the wheel are not going to be confused by anything happening with the bluetooth modules.  The bluetooth module is used to broadcast data and take in commands.  Unless one of those command is "play dead" using many apps from many phones will not break the wheel.  If the wheel can connect to 1, or 2, or 100, apps/phones at the same time it's because the bluetooth chip was designed too.

I really don't want anyone becoming unnecessarily scared of using WheelLog or the official Kingsong app.

I am not saying Kingsong or WheelLog apps are dangerous and I keep on using them, just not at the same time anymore.

At https://github.com/EGG-electric-unicycle/documentation/wiki/MicroWorks-30B4-30kmh-controller-board-with-bluetooth it is said that " NOTE: all the bytes sent in the commands should have a delay of 500ms between each of them. " and that might be easily violated if more that one app talks to the wheel at the same time. It though does not say what the consequences of a rapid succession of commands are: perhaps they are just ignored and all this is not an issue. - Can anybody confirm?

But as you say " Unless one of those command is 'play dead' ..." with all the blutooth background noise around us it is conceivable to me that some "random" combination of signals might disturb the wheel. Since the Kingsongs do not have a device pairing feature and bluetooth is on all the time to me they seem susceptible to such behavior. 

Or do you know of any mechanism in KS wheels that protects the wheel from such (random) interference?

[JumpMaster]

@RenaissanceMan

Neither app sends much data to the wheel. WheelLog sends two commands to ask for the wheels serial number and version when it connects. It can also request the hor via the Pebble Watch. The KingSong app does the same. The wheel acknowledges any command by beeping. Other then that the apps are only listening to the data been broadcasted.

[RenaissanceMan]

4 hours ago, JumpMaster said:

@RenaissanceMan

Neither app sends much data to the wheel. WheelLog sends two commands to ask for the wheels serial number and version when it connects. It can also request the hor via the Pebble Watch. The KingSong app does the same. The wheel acknowledges any command by beeping. Other then that the apps are only listening to the data been broadcasted.

@JumpMaster

I guess I need to apologize here: I sincerely respect your work on WheelLog, have no doubt but trust in your expertise in such enterprise and really appreciate and also keep using your software! (I've  even started exploring options to port the Pebble part to my Samsung Gear S2; have already established the Tizen development platform and, of course, would submit the code to be integrated into your WheelLog project.)

My criticism is NOT about anything specifically related to WheelLog (or the Kingsong apps) but about the bluetooth interface of Kingsong or the undefined state of it, at least to me at present. So far I have not found an explanation of how Kingsong makes certain that only sensible, valid and legitimate bluetooth messages are accepted and processed. And since my recent KS16 failure occured in co-occurance of multiple apps connecting to the same wheel I am somewhat - uhm - sceptical and possibly worried about the safety of our beloved wheels because of this.

Maybe MicroWorks knows the answer to this. I have no contact there, does anybody?

[HEC]

6 hours ago, JumpMaster said:

The KingSong app does the same.

Well KS original app does much more - you can set up also speed limits, unlock the speed, set the light modes and voice mode and indeed update FW (while not riding only of course)

[HEC]

1 hour ago, RenaissanceMan said:

So far I have not found an explanation of how Kingsong makes certain that only sensible, valid and legitimate bluetooth messages are accepted and processed

That's basic two way serial communication (like with or via modem) using in most cases at least two level protection if programed correctly. First will be "high level" handshake where each command is being confirmed / acknowledged as received correctly and then there should be at least some basic control checksums or data parity included to avoid interferences or miss-received low level data. In most case there is also low level data signalling or some other method in place to further increase resilience. In no way would device just blindly receive any "random" data or commands and simply try to process them without any further check in place. That doesn't indeed exclude some unwanted bug which might result in some unexpected behaviour so of course precautions should always be taken and limiting access to the wheel only to one app at the time seems fairly reasonable. Unless you'd need to change light or voice settings or adjust speed alarms on the wheel there is basically no need to use KS app at the same time as WheelLog.

[JumpMaster]

9 hours ago, RenaissanceMan said:

 

I guess I need to apologize here:

@RenaissanceMan

Nothing to apologise for.  I'm not a professional programmer so any criticism is well received.  I agree it would be possible for data to become corrupt but highly unlikely that it would still be valid data.  KingSong do not perform any extra checks on the data above what the Bluetooth protocol does.  Maybe that's sufficient but I don't know enough about it to say.

Adding another watch to WheelLog would be fantastic.  Shame it's a Tizen though 

 

8 hours ago, HEC said:

there should be at least some basic control checksums or data parity included to avoid interferences or miss-received low level data.

Interestingly Ninebot have a two byte checksum on every packet of data.  It means that in a typical 20 byte packet 10% is checksum.  I think it's leftover from when they were using Serial over Bluetooth in Bluetooth 2.0 but it's good that they kept it.  If I was designing this from scratch I'd probably do something similar.  Although as I said above maybe the Bluetooth LE protocol have a checksum/error checking algorithm built in.

[Valery De Smedt]

I had exactly the same problem on Sunday : after a short and peaceful ride, I stopped in front of my front door and when I tried to turn it off and noticed it was not balancing anymore and refused to turn off. I let the wheel there for a while and when I came back to it, I noticed it was off and won't turn on on anymore.  After reading this thread, I went to my dealer who gracefully replaced the fuse and half an hour later I was on my wheel again.  Thanks a lot to cityzen.be for his great support !

 

N.B: Was on 1.20..  just did the upgrade to 1.22 

Edited September 13, 2016 by Valery De Smedt