I've found the schematics and also from what ns gathered, I believe the difficulty to it is in a malfunctioning MOSFET (part AO3409).

You are watching: How to check mosfet on motherboard

How perform I test if the MOSFET is certainly faulty? I have actually a multimeter however I'm not sure exactly how to proceed.

Relevant schematics are linked here (part Q7 close to the top)

EDIT: PROBLEM SOLVED, in good part many thanks to /u/oerkel47! !!! i bought a new mosfet AO3409 to replace the defective mosfet in ~ Q7. After part tricky soldering (it's my second time soldering something), I readjusted the mosfet and also it resolved the backlight issue!


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· 3y
TV repair or capacitor replacement? Please confirm you have actually read these pages first:

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https://www.smashville247.net/r/AskElectronics/wiki/repair#wiki_bad_capacitors

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· 3y

So I had the specific same problem with my 7559, I have actually replaced the Q7 mosfet a couple of times already. As soon as the display is unscrewed indigenous the bottom plastic case, it transforms on and everything works, yet once ns screw the hinges that host the display to the plastic case, the sparks and also breaks, then it will certainly start typically with no backlight. I have tested that there is ~18V throughout gate and source. Any suggestions top top what i need to do next?


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Mod · 3y

TV fix or capacitor replacement? Please confirm you have actually read these pages first:

https://www.smashville247.net/r/AskElectronics/wiki/repair/tv

https://www.smashville247.net/r/AskElectronics/wiki/repair#wiki_bad_capacitors

If those pages doesn't help, permit us recognize here and also we'll usage the feedback to assist improve the wiki. Thanks!

Please note that you might get more precise aid by first posting in r/tvrepair

I to be a bot, and this action was performed automatically. You re welcome contact the moderators of this subsmashville247.net if girlfriend have any type of questions or concerns.

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