thanks amberwolf, for now ,inside box everything is crystal clear, mosfets are all exactly the same in my multimeter measurements,
As previously stated, you may not see the problem with that kind of measurement. You may have to measure them under load with active currents flowing. To do that you'd probably have to take the out of the board and build a test rig emulating that used in their manufacturer spec sheet to test them with, and compare the results with the spec sheet. If they are not within the range the spec sheet provides, then they may have a problem.
If they are working but not being fed the correct signals from the gates, they won't turn on or off properly.
If the gates are not being fed the right signals from the MCU, they won't send the right ones to the FETs.
Etc.
Also as previously stated, it's not just the FEts that are on the battery bus. To be sure you find all of these, you would have to reverse engineer the controller to draw up a schematic, and find all the parts that are on the battery bus, then test each one compared to it's spec sheet values, to see if any of them might be damaged.
only thing i have found are 6 resistors (1R1 1.1ohm) ... 3 are connected to phases , and the other 3 to gnd (or bat +), i cant remember now but i have replaced them with nearest i have found around 1026 size 1R0 instead 1R1!!... still trying to find something else in top board, because these 6 smd resistors were on the bottom board, if cannot see anything else maybe i will try on the scooter again to see if torque power is recovered!!!
If there were resistors in the phases, they are probably current monitoring shunts.
Were they damaged? If not, why replace them?
If they *were* damaged, then very high current must have flowed, which would also probalby have damaged the FETs, possibly the gates, etc.
If you change current-measuring shunts to a different value, then the controller can't measure the current in the phases correclty and cannot operate as designed.
If the resistors are changed to a value that causes the current to be detected as higher than reality, the controller may just see overload in all situations and shutdown.
If they're changed to a value that causes current to be detected as lower than reality, the controller may be damaged by the actual real overcurrents that are then created.
If they are instead gate resistors between gate drivers and FET gates, then changing their value affects how fast the FETs turn on and off, or whether they do at all depending on the timing and length of the signals from the gate drivers.
