Hp 15-ab254sa laptop water damaged - Laptops power input circuit 

you are right

Yes , the first is p-channel and that`s why the gates were not connected together

true..

indeed

If it is a P-channel why did it work when he put 25V on the gate?

No.. 1 N-type and 1 P- type. Bad move with jumper wire

Yep! There are capacitors on the gates of those two mosfets. Looks like due to the water damage capacitor connected to the gate of the first mosfet was partially shorted. Smoke that Sorin fell after applying 25 volts to the gate was most likely coming from that partially shorted capacitor.

@@laptopDoctorKZN According to schematics, both input mosfets are N-type and both gates are driven by the BQ chip.

Ve been following for 7years

That's crazy

Only twice a day, be certain to floss between the caps and only change the thermal paste on the second Tuesday of the week. I think that would do it. 😁🍻

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yeah he put 25v vgs instead of 6. no wonder something smoked

Haha, I wondered this a while ago, myself. Oil-based is generally not good for electronics so perhaps he decided to shy away from becoming an advocate to others' mistakes. I use it on thermal paste but thoroughly clean it with IPA afterwards.

If I remember correctly, he stopped using the lighter fluid after he bought the thermal camera, he was using it to find hot components on the board. For cleaning i always remember him using isopropyl alcohol (isopropanol)

would take too long 🙂

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Or 25v from ground of laptop, plus to gate, but not source -gate?

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I think it the tip of the multimeter test probe that it slipped from the test point

He did put 25V back into the circut with his PSU, thinking that did the pop, not sure how the tunneling affected it though

@Dohcom1 zoom at the video and you will see its a coincidence that it happened when he put the 25v you can clearly see it slip off

@@jaraalbert Hi, Thats not a multimeter test probe, it a PSU probe at 25V, He couldnt have shorted across the board unless he went other way, and he never slips!

@Dohcom1 Well let me tell you that they are multimeter probes but connected to a power supply i have been watching Sorin for years back when he worked at the mall and he also showed his new home setup when he started at home

F “calibrated wire” don’t be lazy and use the correct parts

@@MrPnew1 So you've never broken a pad or had to fix a trace on a board? I've been soldering going on forty years now. Although up until recently I started getting more into micro soldering or smd work. I recently purchased a microscope and hot an air station to add to my bench. People can agree or disagree on whatever, although there are times where you need to jump something either temporary or permanently, that's just the way it is.

⁠@@marksplaceagreed, but it’s bad practice to use jumper wire to bypass fuses, coils and mosfets. I never suggested not using jumper wires for trace repair.

@@MrPnew1 Sorin mentioned many times he only does that temporarily to see if the said component is indeed faulty to save time. He does replace the components later (either has to order or looks for one on donor boards)

@MrPnew1 ​I ended up buying some 30awg wire as it seemed like a nice size for small circuits. That's when I got a little curious as to what it would take to burn it up. I ended it with 5v and 5amps and the wire didn't even get warm after leaving it sit there for upwards of a minute. I didn't want to stress out my power supply any longer knowing that any more than that is basically useless anyways as a make-ship fuse. I'm going to try and find the smallest wire I can and repeat the test. If one could use some small wire as a fuse it wouldn't be a bad thing if that's all you had at the moment. Although I think I'll also be searching for a kit of various size fuses to keep on hand as that would be the better choice. IMO