How to test a MOSFET? testing a MOSFET short or not
We should test MOSFET in 3 corners, those are
Drain to Source
Source to Gate
Drain to Gate
When testing on a motherboard make sure that motherboard not powered or not plugged in and don’t connect with battery.
Drain + Source = OL in 200 Ohm Range, it will have at least 100s Kilo Ohms
Drain + Gate = OL in 200 Ohm Range, it will have at least 100s Kilo Ohms
Source + Gate = 200 Ohm Range, it will have at least 100s Kilo Ohms
Probes can be in any sides, that does not matter
If low reading like 1.0 ohms or 2 ohms between pin Drain to Source, then that MOSFET is in On State. Then you can touch/short with a tweezer between Gate pin and Source Pin so the MOSFET will come to Off state. Then Check again.
After Shorting the Gate and between Source, still shows low ohms value then desolder that MOSFET and check that gain to make sure.
Good working MOSFET will have these ranges in Ohms Mode in DMM Digital Multi Meter or Ohm Meter
