Diode and mosfet onboard testing

[LS]

Hi,
I have a fault on a laptop motherboard:
After I plug in the connector the power supply protection stop the power.
I think the cause it's a bad connector but I desolder it and power the
motherboard with two cable directly but the problem remains the same.
I test the ohm value on power connector and the tester return me approx. 450
ohm.
No component with visible fault (I control with a microscope), no component
with heat surface.
Someone told me to control diodes,. resistors, electrolitics, and mosfet
but how I can test a diode without
desolder it and an 8 pin mosfet ?
Someone can help me ?
thanks

 

[Gerard Bok]

I have a fault on a laptop motherboard:
After I plug in the connector the power supply protection stop the power.

No component with visible fault (I control with a microscope), no component
with heat surface.

My next step would be to test the power supply's protection
circuit.
Use a separate (controlable) load and see at what current the
supply kicks out.

 

[LS]

I test the motherboard with another power supply (work ok) and its led
flashing continuously
I exclude a problem to the power source, what is the next test you advice
me.

thanks so much

Luca