meiqu controller problem

[terki]

Hello, 17A aliexpress MEIQU controller stop working. When learning line is connected, wheel rotates only when helped first a bit (Ananda mid motor converted to external controller). Learning line open, does not react on thumb throttle. When connect DD motor, same with learning line. With the learning line not connected, and push throttle, it hears from motor ticking sound, witch frequency goes higher as throttle more pushed. Mosfets not short. With another same type controller bike work OK.
Controller cost 26eur, free shipping, so my question is just for education.

 

[terki]

No error codes on S866 LCD, both tried systems with hall sensors.

 

[amberwolf]

If it's a sensored-only controller, then there's probably an issue with the controller reading the hall sensors.

Or it could be having a problem driving one of the phases; either a connection issue or a FET or gate drive problem.

Since you have more than one of the same controller, you can test to see what specifically is different in operation between one that works and this one, under the same conditions. Easiest if you have an oscilloscope, but you can do some measuring with a voltmeter, ammeter, and ohmmeter for certain kinds of problems.

 

[terki]

Thank You, it is a three-mode, so gate drive problem is most realistic, cause FETs are not short - lot of info how to test them. 5V line is OK too.

 

[amberwolf]

FETs don't have to be shorted to be damaged. They can read perfecly normal in an unpowered resistance test and still have problems in actual operation. ESD damage from handling of parts in manufacture can cause all sorts of wierd damage.

The gate drivers are usually only damaged by FETs that were themselves already damaged, if there's no factory-manufacturing defects or environmental damage.

 

[terki]

Thank you again, this is valuable info for me - other sources let believe that measuring in unpowered stage will give 100% correct data.