TSDZ2 sometimes it stop assistance

Hi,
first of all i introduce myself, i'm Maurizio and this is my first post. I like very much electronics and since some months ago also the ebikes!
I have a rockrider 5.3 with tsdz2 motor, and until it worked fine i was very happy of this ebike.
Now my tsdz2 has about 400km and it presents a very sneaky defect. Sometimes, the motor stop the assistance completely, when it happen the display remain on but it doesn't indicate the speed. If i switch it off and then on again the battery indicator show only one segment on but the battery is full, the speed not indicated correctly(00 on the display also when bike move) and nothing works. After some switch on and switch off suddenly all come back to work correctly.
I gave a look inside the motor but all seems to be ok (i haven't removed torque sensor) could someone help me to find the problem? Which part i should change?
Thanks in advance and best regards.

Maurizio

Doubt it is the torque sensor.

1: Loose/improper connection of the cables. Inspect and use a very little electronic water proof substance on each side before re=assembly. Also check your battery connection if you have a HL type battery as I have seen those brand new with bad solder jobs, you have to remove the aluminum cover to get to these, and even had them come in a few times with the leads mixed up.

2: Do the same thing on the display connections for the mode module, brake cutoff's (if applicable) and throttle. While these items are unattached with the main wire connected try to see if it works then.

3: Take out the controller, you will need to remove the drive side cranks to do this as it is held by small bold on that side. In order for it to come out you also have to dig out the factory sealant from around the cable to get enough slack in the wires. Inspect both pin connectors, the two wire one is the torque sensor wire as per above. Check all soldered connections on the controller board.

If none of these work either the controller or display is probably defective and both are parts fairly easily replaceable. In fact all parts are other the than the torque sensor being king of tricky to re-install.

unplug the magnet speed sensor and try it. You don't need the sensor to run but it will cause problems if bad or the air gap is not right.

Thank you very much for your suggestions.
I have tried to unplug the speed sensor but change nothing... The big problem is that this defect appear only sometimes and then it disappear.
I have checked some connections(torque sensor and hall sensors) but i haven't removed the controller in order to check well also soldered pins.
It seems that the controller suddenly switch off but the display remains on... a possible fault could be that there is a bad connection on the white cable in the display... If i understood well, if this cable disconnct the controller switch off but the display remains on... I have to check well.

Intermittent problems are almost always in the wiring or connectors. Could be something loose, or something spread apart, broken inside the insulation but connects when in right position, etc.


Occasionally it is bad solder joints on boards or connectors.

Very rarely it is broken leads on parts mounted on the boards.

Very rarely it is broken traces on boards.

Hi all,
I have found the cause of the defect!
Yesterday i have cleaned the bike, after the cleaning, i tried to switch on the motor and the battery indicator shows only one segment... but the battery was just charged!!! Obviously the motor was stuck, no assistance.
After some tentative i have found that if i move the speed sensor the bike start! This is very strange! How is possible that the speed sensor block the entire controller?
By the way i have repositioned the speed sensor and the defect disappear. I have noticed that if the controller is stuck and i disconnect the speed sensor suddenly it restart!

Maurizio