Replacement MOSFET for mo9300m

[chiefcrypto]

Hi all,

First up I'd like to say this is my first thread so thanks for lending your collective minds to help me.

I'm looking to replace a bad MOSFET on a Asus x556u motherboard, from what I can see (it's a bit burnt) it's a mo930m, just wondering where I can get hold of one or what can be used to replace it? This would be my first component level repair so I'm not particularly experienced in sourcing these parts.

Thanks for the help.

[diif]

Re: Replacement MOSFET for mo9300m

You can do a search on here for P0903BEA.
I get small ICs from Aliexpress.
I have some somewhere around here, I ordered 10 last year.

[chiefcrypto]

Re: Replacement MOSFET for mo9300m

Thanks for the reply! Guessing that's the part I need then.
If you find one let me know, I'll happy take one off your hands, at least I'll know it won't go boom that way.

How does one find out what components are compatible for these kinds of things? Is it a case of matching resistances and operation currents or am I totally off the ball?

Also it's nice to see a fellow midlander.
Thanks

[chiefcrypto]

Re: Replacement MOSFET for mo9300m

Also got a multimeter today (god bless Amazon prime), tested the MOSFET and it's reading 0v on all pins, diode mode shows 0.457.
I'm fairly certain that proves it's blown it's guts out, open to other opinions.
Thanks

[diif]

Re: Replacement MOSFET for mo9300m

Can you take a photo ? 0.5v in diode mode is what I'd expect to see.
Is there another similarly marked MOSFET nearby ?

[chiefcrypto]

Re: Replacement MOSFET for mo9300m

You see that's what got me, 0v DC is obviously a warning sign, but the diode mode seemed to contradict it. Especially since in a Paul Daniels video I watched this exact diode was reading that. I'll send over a pic when I'm back in the workshop.
Thanks

[chiefcrypto]

Re: Replacement MOSFET for mo9300m

Here the PD video for reference. https://youtu.be/ayu7L40hRVI around 12:25 is where he shows the diode mode, after he's replaced it with a working MOSFET, the exact same one went bad in the board he's fixing.

[diif]

Re: Replacement MOSFET for mo9300m

It could just be that one MOSFET, whilst I can't find the P0903BEA I ordered, I do have some AON7200 which are a suitable replacement.

I use this to find suitable replacements. https://alltransistors.com/mosfet/

Where in this great shire are you ?

[chiefcrypto]

Re: Replacement MOSFET for mo9300m

Seems to me like it's too much of a coincidence to not be. I'm in Syston, Leicester, I can give you a full address, will PM you.

Much appreciated.

[diif]

Re: Replacement MOSFET for mo9300m

Happy to help, you're not far away from me.

[Retro-Hipster]

Re: Replacement MOSFET for mo9300m

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[Retro-Hipster]

Re: Replacement MOSFET for mo9300m

You see that's what got me, 0v DC is obviously a warning sign, but the diode mode seemed to contradict it. Especially since in a Paul Daniels video I watched this exact diode was reading that. I'll send over a pic when I'm back in the workshop.
Thanks

On this, when you say "0v DC" on these pins, do you mean when it is in an on state? When you are testing n-channel mosfets, you would normally go on diode mode and then put the black/comm of your meter on the drain, then touch the gate with the red lead to turn the Mosfet on. Then you would test it from Source to drain to see if there is connectivity. (Assuming this is out of circuit.) Then, if you short the gate to the drain, it should turn off. If it is off and then you are reading a short between the pins, then the mosfet has failed. (Though, in some cases they fail open. Mainly they fail closed.) If it is in circuit, I would expect to see no connectivity between the source and drain..

[chiefcrypto]

Re: Replacement MOSFET for mo9300m

Just tested it again and in fact the MOSFET is seeing 19v, must have not made a proper connection when I tested it last time. So it seems like despite it being visibly discoloured and the pads looking terrible on it, that MOSFET is working as it should.
Will be trying to re-flash the BIOS next.

Thanks