Hall sensor ID

Hi

I'm trying to repair a food mixer where the speed of the motor is detected using a hall sensor.

I have eliminated the components other than the microcontroller or the hall sensor. I figured the hall sensor is easiest to replace first. The markings on it are 137 033a.

I have swapped it with one with markings of 137 OH33 but it seems the control board isn't registering it. I think it might be a pole issue?

I don't have a background in electronics, just an amateur.

 

The fault is that it starts slow then speeds up uncontrollably quite quickly until it maxes out.

I figured the feedback loop that measures the speed failed, and it was either the hall sensor that is positioned very close to a doughnut shaped magnet on the drive shaft or its in the controller. Perhaps one of the 2 transistors is faulty on the control board too.

I measured +5vdc between 2 of the legs on the hall sensor. Not sure how to test the transistors or the microcontroller.

 

Sorry I really struggled to get many details. It's an Andrew James mixer https://www.goodhousekeeping.com/uk...677922/andrew-james-5-2l-food-mixer-aj000194/

I've attached photos of the board (only letting me upload one at a time)

 

Rest of the images:

https://ibb.co/hXkPjdj
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https://ibb.co/vPRC5WG
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https://ibb.co/SQssYdD
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https://ibb.co/ccrzTDn
https://ibb.co/VwcLrpB