Other Mastermind “did not” switch on. Then, it fixed itself.

Ridescaper

Member
Apr 2, 2023
17
11
Berlin - Milan
I wanted to share with you an interesting behaviour my Kenevo presented. I titled the thread with “did not” since the bike fixed itself.

What happened?

After several weeks of mountain rides, I heard the well-known creaking noise from the headset, mostly on a bumpy surface. After reading up on it I figured the headset needed some greasing. After servicing the headset (taking it apart, greasing it, and putting back together) I noticed that I couldn’t turn on the bike anymore. I clicked repeatedly and held the button down for a while.. nothing.

IMG_7004.jpeg


I cleaned the battery connections (thinking maybe I contaminated the pins somehow), but still nothing. Battery LEDs worked when I connected the charger.

After some online research, I found similar issues from Turbo Levo owners, who had rectified the issue by removing the Mastermind from the frame and disconnecting and reconnecting the wires. That’s what I planned to do next. I noticed that I didn’t have a small enough torx key (T10), so I was heading to the hardware shop. I took the bike and planned to ride it turned off.

Just after about a 600-metre ride, the bike turned on by itself.

I stopped and turned it off. Then, I tried to turn it on again - nothing. No signal.

I started riding again, and it turned on. I stopped and turned it off. Then it turned on after every second click. I clicked first, nothing, click again - switched on. Gradually, it has returned to its normal behaviour. The next morning, I could turn it on again from the first click.

I can not explain this behaviour. Does anyone have any guesses? Could there be a mechanism that the motor somehow tries to kickstart the Mastermind after riding in a switched-off state for a while?
 

dave_uk

Member
Nov 15, 2021
103
53
uk - Staffordshire
My Kenevo has done something similar:


Has your bike been ok since the issue?
 

Ridescaper

Member
Apr 2, 2023
17
11
Berlin - Milan
My Kenevo has done something similar:


Has your bike been ok since the issue?
Yes, there haven't been any anomalies whatsoever. It may have been caused by motor reverse movement when I serviced the chain. I had the battery disconnected and out of the bike, but that's my only guess so far. Just a software glitch.
 

dave_uk

Member
Nov 15, 2021
103
53
uk - Staffordshire
Cheers for your reply.

Decided to pull the motor out and check the connections - which are FINE! Typical.

Now need to check rest of wiring.

But whilst I had the motor out I found this:
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,145
4,676
Weymouth
It is well known that the motor can be activated by crank rotation which is why the recommendation has always been to remove the battery before doing any drivetrain maintenance. ( albeit it has never happened to me with Bosch motors).

As far the rest of the progressive recovery from refusing to power up, a poor connection ( high resistance disconnection)is the most likely culprit and the fact it slowly rectified itself was possibly due to current being provided which eventually "pushed through" the poor connection. The most likely cause being water ingress and/or corrosion.

I dislike top tube mounted controllers ( e.g. Mastermind/TCU) simply because an enclosed ally or carbon tube is a pretty hostile environment. One thing that can happen is condensation. I would remove the Mastermind/TCU and check the connections and ( assuming it is the same as the gen2 Levo) the connectors on the tails of those wires.
 

dave_uk

Member
Nov 15, 2021
103
53
uk - Staffordshire
well known that the motor can be activated by crank rotation which is why the recommendation has always been to remove the battery before doing any drivetrain maintenance.
Oh, not by me. DOH.

Suppose that is a good heads up to me and other emtb owners!

Still, glad I got the motor out as now I can correct the gear-cable and brake-pipe issue, which would have become fatal.
 

Barnicles

Member
Aug 8, 2020
57
20
Uk
Mine is doing this at the moment. It's just had a new battery under warranty and after it's first (very wet) ride it's now playing up. It's powered up once or twice but mostly won't switch on. Even with the reverse crank rotation nothing is happening. Is there anything I should check before take it to the shop for a checkover? Battery has been charged fully and connections dried.
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,145
4,676
Weymouth
I dont know how similar in construction the Mastermind is compared with the TCU but on my 2019 Levo I removed the TCU and applied insulating tape around its waistline ( a seam between the top and bottom of the unit) also covering the USB port which was poorly protected by a ill fitting rubber bung. I made sure the tape fully covered the connection of the 2 wires into the bottom end of the TCU. I then wrapped amalgamating tape around the the connections of the 2 wires further down the top tube. Lastly I used a liquid gasket between the TCU and frame. By smearing a little grease on the frame face the liquid gasket will only adhere to the TCU...so removing the TCU again is still possible. I never had any TCU problems.

Oh....also take a look at where the cables from the TCU/Mastermind make there way behind the shock on their way down to the motor. I used grease at the point they re-enter the frame to block progress of any water tracking down those cables. None of this should be necessary......but if you want a reliable bike........!
 

Ridescaper

Member
Apr 2, 2023
17
11
Berlin - Milan
This is a small addition to this Mastermind TCU troubleshooting thread. After several months of staying offline in my storage, I could not power the bike up. I was about to suspect that temperature changes may have damaged the Mastermind (I did charge the battery fully). I want to share this pro tip from one of the local technicians here:

- it can happen that the Mastermind falls into a "sleep mode"
- sometimes, the battery charger may wake it up, but if it doesn't, his advice was the following:

While the Mastermind is connected to the bike, connect it to a computer via its USB-C connection. No software is needed.

I did just that; I happened to have my Macbook with me and could use its charging cable. The Mastermind powered up immediately and continued working flawlessly after that.

I hope this helps someone who may find themselves in a similar situation. :)
IMG_8067.jpeg
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,145
4,676
Weymouth
This is a small addition to this Mastermind TCU troubleshooting thread. After several months of staying offline in my storage, I could not power the bike up. I was about to suspect that temperature changes may have damaged the Mastermind (I did charge the battery fully). I want to share this pro tip from one of the local technicians here:

- it can happen that the Mastermind falls into a "sleep mode"
- sometimes, the battery charger may wake it up, but if it doesn't, his advice was the following:

While the Mastermind is connected to the bike, connect it to a computer via its USB-C connection. No software is needed.

I did just that; I happened to have my Macbook with me and could use its charging cable. The Mastermind powered up immediately and continued working flawlessly after that.

I hope this helps someone who may find themselves in a similar situation. :) View attachment 133461
The TCU had its own replaceable battery...............does the Mastermind have a cell ( Lithium) battery that is changeable?? If not then it has a non changeable lithium battery charged from the main battery but possibly only when the bike is ridden as opposed to merely switching the bike on. The fact that the Mastermind woke up just by plugging in a laptop suggests it was flat and the laptop charged it.
 
Last edited:

Ridescaper

Member
Apr 2, 2023
17
11
Berlin - Milan
The TCU had its own replaceable battery...............does the Mastermind have a cell ( Lithium) battery that is changeable?? If not then it has a non changeable lithium battery charged from the main battery but possibly only when the bike is ridden as opposed to merely switching the bike on. The fact that the Mastermind woke up just by plugging in a laptop suggests it was flat and the laptop charged it.
It could be it but I wonder why the bike battery didn't keep it charged.
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,145
4,676
Weymouth
It could be it but I wonder why the bike battery didn't keep it charged.
if indeed it has a 3.7v rechargeable lithium battery the Mastermind will also open and close a charging circuit from the main battery. That may be when the bike is switched on or possibly only when the bike is in motion/being ridden depending how it is programmed. The Bosch Smart /system controller is charged by the main bike battery and the rechargeable battery can fall below a critical state of charge if left long enough without the bike being used......but we are talking about several weeks or months perhaps accelrated by cold temperatures. It is certainly advisable to start up a bike occasionally if it is being stored unused for any length of time.
Recommendation for charging such a battery is 5v/600Ma..............typical of a USB connection to a laptop etc.
 

Ridescaper

Member
Apr 2, 2023
17
11
Berlin - Milan
I stumbled upon this Technical Bulletin from Specialized that gives the same info/guidance. Earlier searches with the problem description resulted in nothing; perhaps they need to work on SEO a bit more :)
 

Attachments

  • Turbo Kenevo Expert MasterMind TCU-TCD Not Powering On.pdf
    1.4 MB · Views: 35

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