Hello everyone, i have a roidmi eve plus with non spinning LDS(The sensor on top). The board you see is on the sensor assembly. I measure 5v coming to the board, and 2,3v on the pwm pin. The mosfet on the top left corner measures 2,3v on the gate and when i turn the vacuum on i have continuity between drain-source. When i remove the belt connecting the assembly to the motor(so it has no load) it spins, but if i touch it ever so slightly it stops. Mosfet has A2 3 markings and from what i can find Vgs(th) is 3Vmax. So i guess 2.5V on the gate is enough to drive the motor. Is there anything else i can check??
Any help appreciated

 

So i guess 2.5V on the gate is enough to drive the motor.

How are you measuring the 2.5V?
It sounds as though 2.5V isn't enough to turn the FET on fully. Do you have a 'scope to check if the PWM input pin actually has 0-5V switching waveform?

 

How are you measuring the 2.5V?
It sounds as though 2.5V isn't enough to turn the FET on fully. Do you have a 'scope to check if the PWM input pin actually has 0-5V switching waveform?

Sadly no, i check with a multimeter. I cant find the exact component to be sure about Vgs th , but from what i have seems ok. I can replace the whole lds but i want to make sure this will solve the problem. Also doesn't drain-source continuity mean it turns fully on?

 

Hi ama,
There is possibility that the motor requires a square wave drive of say 50/50%, so a 5V amplitide signal may only read say 2.5V on a voltmeter. You need to check with a Scope.
E