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My laptop died recently and I’m testing the motherboard. I’m led to believe these two MOFSETs on the board may be part of the issue PQ301 and PQ302.

Using a multimeter continuity and diode mode; PQ302 beeps between S and D on continuity mode and 0 resistance on diode mode. I’m led to believe that means it’s defective. PQ301 does nothing on both modes between the pins.

I’ve been testing them in opposite pairs i.e pins 8 and 1, 7 and 2 etc. Am I testing them correctly and if so should I go ahead and replace the mosfet and see what happens?

Here’s the diagram I’ve been looking at. Just hoping for some guidance. Thanks.

enter image description here

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I’ve been testing them in opposite pairs i.e pins 8 and 1, 7 and 2 etc. Am I testing them correctly and if so should I go ahead and replace the mosfet and see what happens?

Yes, you are correct, if you have the correct polarity of your multimeter leads you should at a minimum see a diode drop between Pin 8 to Pin 1 of PQ301, best case a low ohm short.

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    \$\begingroup\$ Except there's a whole laptop full of parts in parallel to the FETs. Measuring this kind of stuff in circuit is just not a good idea. \$\endgroup\$
    – JRE
    Commented May 15, 2019 at 5:46
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    \$\begingroup\$ @JRE Fair enough, but measuring an un-powered component in circuit will measure lower than expected, not hi-Z. \$\endgroup\$
    – sstobbe
    Commented May 15, 2019 at 5:53
  • \$\begingroup\$ What is meant by low ohm short? On PQ301 I get .972 ohm between 8, 1 and .664 ohm between 7, 2 and .262 ohm between gate and source. \$\endgroup\$
    – muhammad amer
    Commented May 15, 2019 at 12:15

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