KT Sensorless Controller - Yellow Phase Short - HELP

Hi guys,

https://www.youtube.com/watch?v=e09wIGcGsxU

The above video is my circumstance.

Bike only had 46km before motor stopped working. Appears that the yellow phase wire is shorting to the other 2. When the yellow and green are connected, motor has resistance, yellow and blue, resistance, blue and green, no resistance.

This is the controller that was purchased
http://www.pswpower.com/ven.php?cargo.2016-3f-28ym

Note: I haven't tried to solder / desolder anything yet

Battery connected was a 52V (14S) battery.

I tried to zoom into the controller circuit board the best I could, I didn't notice anything too obvious in terms of solder crossing over into places it shouldn't have.

Controller was low cost, but hard to replace now in the midst of the corona pandemic.

Any help? Suggestions?

Thank you!!

Almost certainly you have shorted (blown) FETs in that phase inside the controller. You'll need to replace all the FETs in that phase (preferably with the same kind), and potentially the gate drivers for them.

There's a lot of controller repair threads that may have info you can use. Some of the ones in the lists below are relevant; there's many others not listed in these.

https://endless-sphere.com/forums/search.php?keywords=replac*+*fet*&terms=all&author=&sc=1&sf=titleonly&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search

https://endless-sphere.com/forums/search.php?st=0&sk=t&sd=d&sr=topics&keywords=%2Afet%2A+upgrad%2A&sf=titleonly

https://endless-sphere.com/forums/search.php?st=0&sk=t&sd=d&sr=topics&keywords=%2Afet%2A+blown%2A&sf=titleonly

https://endless-sphere.com/forums/search.php?st=0&sk=t&sd=d&sr=topics&keywords=%2Afet%2A+short%2A&sf=titleonly

etc.

There is also information on http://ebikes.ca in the Learn - Troubleshooting area on testing.

Thank you Amberwolf, always coming to the rescue, much appreciated!!