My measurements on the good motor showed:
Forward: G0 = 0V, G1 = PWM (switching from 7-15V), G2 = 5V, G3 = 15V
Reverse: G0 = 5V, G1 = 15V, G2 = 0V, G3 = PWM (switching from 7-15V)
(G0, G1 = the left mosfet, G2, G3 the right one, counting from left to right when the front of the roomba is facing you).
I think they are their gate readings. Pins 4,2,4,2 of Q60, Q59.When testing this stuff make sure to use a limited current power supply. And as stated above, make sure the mosfet control signals (gate) are valid before soldering in new mosfets and the 0.1R shunt
Upside down and backward.G0, G1 = the left mosfet, G2, G3 the right one, counting from left to right when the front of the roomba is facing you).
My measurements on the good motor showed:
Forward: G0 = 0V, G1 = PWM (switching from 7-15V), G2 = 5V, G3 = 15V
Reverse: G0 = 5V, G1 = 15V, G2 = 0V, G3 = PWM (switching from 7-15V)
(G0, G1 = the left mosfet, G2, G3 the right one, counting from left to right when the front of the roomba is facing you).
G0 = Q60 pin 4
G1 = Q60 pin 2
G2 = Q59 pin 4
G4 = Q59 pin 2
Updated from a1robotrepair comment - refer to next post for details
a1robotrepair wrote:Checked my notes. Forgot about D63 & D64 reverse biased Schootky diodes used to collapse the motors EMF while stopping or slowing down.
They are from the motor connection contacts pins 1 and 2 to System Return, bypassing the motor current sense resistor.
They will have a very low forward break over voltage, below 0.2V current dependent.
If one of the FETs has failed closed or driver circuit is exciting the gate, spinning the wheel will try to push current against itself.
razvanmitre wrote:... what should I do? ...
a1robotrepair wrote:Q93 counterpart is the common device to both P channel FETs gates. Look for your problem in that area. SysRtn on Q77, Q88 counterparts. R132 counterpart not shorted.
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