At 12:11 it seemed like the IC next to the inductor had a small crack. Could also have been some dirt

Hi Alex, I am a electronic hobbyist, often watch your videos, with your knowledge and skills I learnt a lot and today I fixed a hard drive one of teachers and very glad that it worked out well. Just thanking you will be less to appreciate your sharing skills, knowledge and talent. I am glad that I bumped on to your videos and yes I used lots of flux 😊

I started at 20yr old to to have an AS Degree in electronics and not I'm 74 and still learning to ID the SMD components by watching you name them as you test them. I still have a steady hand to do the micro solder with your help of showing the componants and how you test them. Thank you.

I think we need to check the capacitors of the smps lines ( for leakage ) or the lines that control the gate of the mosfets ( for level of voltage ) or completely change the charging ic and see .

Most of the time, first two mosfets are controlled by the charging IC. Try replacing the IC.

Oh! I can't wait to viewers ideas! I am not a smd soldering person. Just an amateur who likes to watch how Alex fix electronicks :-) So I am excited how far this repair will go.

The charging chip is the likely culprit... even if you jump the two MOSFETs, the charging chip needs to send an AC_OK signal to the Embedded Controller indicating that a charger has been connected to the laptop. That prompts the EC to instruct the 5v and 3v chip to start working

On 12:11 I think the surface of the IC is carcked.

This is the most interesting video you posted so far. Why? Because I have encountered this issue and never figured it out. Is there a part 2 to this?

Puting a wire instead of the two MOSFETs will not fix the problem because AC_OK will not be present. So to solve the problem just replace the two MOSFETs . All Asus laptops have this problem

The only thing I can think of that will be stopping the proper flow of electricity to the main board will be a shorted capacitor somewhere. Usually when microcapacitors short out they can either act like resistors or just no powerflow at all.

You could replace the charger IC at 4:33. It is dead and you could check it on REGN pin when plug in adapter. If it is alive, it will generate around 6V on it.

Maybe you could check the Diode next to the 2 Mosfets you removed.

Hi if there’s no voltage in the gate of 1st mosfet, check the acdrv signal from charging ic, if there’s no schematic available try to look the manually the data sheet of the charging ic and use continuity mode of tester from ACDRV signal if connected to the gate of mosfet. The ACDRV signal is generated of 22v or 24v from charing ic, NOTE: N-channel mosfet is always higher than the source in gate signal

What about a dead bios battery? Sometimes the tiny little battery that maintains bios settings and the RTC (realtime clock) module being dead would prevent the laptop from turning on, I actually experienced this a few times in the past.

Alex did u check the voltages while only battery connected.

Best part at 7:00 keep your goggles handy before watching it.. ..😂😂

I would check the charge controller on the rear of the board, just left of the power connector. It controls the PWM signals to the MOSFETS. I couldn't read the numbers to look up the power, reset pins. Second, I would replace the low side MOSFET you removed. It shows signs of heat damage.

Check 3.3v on the switch if not available verify if the 3.3v and 5.5v circuit is ok, the Start-up ic also needs checking.

Seems to be either Charging IC or 3V/5V voltage regulator issue

Hi Alex. Check for 3.3 volts on bios and super io chipset. If there is 3.3 volts then problem either bios or super io chipset. Good luck

Hi @12:24 I see a module that I think it's for WiFi. Could you remove it an test the board without it? I have laptop that was not power on and after changing many repair shops finally someone figured out. The Faulty WiFi module was the problem. Thanks

This is one of those cases where the short existed, BUT...as it can no longer be seen on the thermal camera, the short was so large that it already blew/opened/destroyed the component internally. This is one of the toughest faults to detect, as you would have to make sure the components are getting the correct voltage. I would pass on this one, not worth the time to diagnose, even with the schematics.

When you added the jumper, make sure it touches the middle pad. might be sensing power good.

Hi alex you said before that you will create a section in the forum for schematic and boardviews are you still going to do it i have a lot of them and i will be in a look at the forum to provide for anyone asking .. salam . RIDA

Since there is no short to ground something might be eating the voltage. Maybe a volt regulator chip ¿ . You might probably see a blinking chip with your thermal camera at back of the board. Or a resistor that gone bad. Resistor will not return any voltage and will not show as a short. So check resistors around charging ic. And also around musfet

Alex, whats the model number of the laptop?

In MacBook I seen this problem when the voltage divide resistors gone bad, and their resistance increased from 47k ?? to 100+k ( as I remember ). Do you have a donor board as this one to check them ? Also 11:03 4 caps on the top, 2 from the right have a strange black dot on it

what is the blob just below the 22uF cap? 09:45

Is that a solder blob bridging the big electrolytic cap and the large surface-mount cap at 10:00?

Besides the liquid metal, since passing 19V trough doesn't turn the PSU off it's unlikely a short after the mosfets. How much power is drawn from the PSU when bypassed mosfets? Of course something isn't opening the mosfet and only passes trough 4,6V, but what happens if you pass like 20V to the gate? Does it allow 19V trough then and if so using thermal cam you might spot the issue. If so then whatever is driving that mosfet is not working. There is always driving circuit for those mosfets, usually a chip near the fets. Of course there are other designs and things such as charging chips or components around those chips could be the cause. Since it is no direct short it will be difficult to find and likely a hailmary.

Fault finding for shorts is obviously effective and deservedly profitable to repair, but it's only one failure mode. Power control on these is dependent upon micro controllers activating mosfets, reading current, sending serial data and "OK" signals to enable startup. Probably not worth your time and a customers money. You could identify all the integrated circuits around the power systems, check them with an oscilloscope to see which ones have data busses, check and interpret comms based on data sheets and narrow down the fault. It must either be a failed IC or a failed passive. Without schematics or reverse engineering it is only guesswork. Thanks for what you share!

hi alex, i'm learning a lot with some channel ,of course yours and i saw twice usb port shorted and tiny bridge water dommage on SUPER I/O chip may be

Hi ! did you have voltage on input of power rail / VCORE ?

I'm confused. You jumped two drains. How did power get to the rest of the board without jumping to the last source. Isn't it like line and load on a gfci?

9:50 what is this blob just at the anode of the AL-Cap?

I think you must check charging IC (BQ Chip) that usually as a voltage source of the gate first power mosfet

I think the diode next to input mosfet is in short because there should no power if mosfets closed but there was. Also there can be super IO problem but need to check stand by powers 3v and 5v is present when after first mosfets injected power or after fixed mosfets issues.

Alex, at 11:30 you can see the liquid metal has flowed down the GPU. Maybe it seeped under the kapton film and shorted the SMD capacitors. Please check it. Use isopropyl alcohol to wipe off the liquid metal residue from the kapton foil.

Replace the charge controller IC that controls the gate pins of the inrush protection MOSFETs?

It looks like they use kicad to design this board. The footprints look familiar. Does some other cad tool have those footprints? (I’m talking about the silkscreen on sot23-3 as well as the elongated pads, also the silkscreen for 0603 and bigger caps/resistors)

At 1.01 check for component 156 1E for short, seems there is a feedback circuit next to its line.

put back the jumper wire and measure all power capacitors. maybe dead resistor cuts power from ICs

Hello Alex, at 10:06 i see a bulge of solder between the electrolytic cap and the other cap?? Or maybe just dirt?

I am happy to see your diagnostic for 5 hours on this board it is not boaring for me 👍

Maybe get a board diagram or if not available you could support yourself with diagram of similar board. Often power supply looks the same or similar but it could lead to fining out the issue.

since the failure mode is not short I think you can deduct all ceramic caps are fine. it might be a burnt resistor or bad electrolytic cap as well as a ic related to power or embedded controller. maybe some diode. i am however just a hobbyist.

Puuh that is really a hard one. I think you tried everything that is possible. Maybe someone have a great idea what could be wrong with this board. We all can learn something new. Thank you for that video. Greets

One thing I have had a bad experience with is Kapton Tape. The material absorbs moisture over time and the resistance of the material goes down reeking havoc with sensitive control electronics. The circuits will behave unpredictively and I suggest you remove any Kapton from devices. Kapton was designed for use in space and not for a humid atmosphere like on Earth.

Sometimes a capasitor if it does not give a solid reading means it's damaged.. Even if it does not give a short bip

look at the solder joint 10:16 maybe it's shorting out or blocking the 19v to go thru...

I have learned a lot from your videos 😊 thanks alot .

Like others wrote, need to check 3.3 around super IO, and check Super IO when try to start motherboard...

I would have checked the 3.3V power supply. If it’s not present obviously the laptop will not work. If I have to guess probably it’s missing, and should first try to investigate why. If it’s present probably the super io is faulty, happened to me in the past. Great video!

i realy love channel and your content! thanks and keep going on!!

Yo. @12:40 what do you test on the gate of MOSFET please ?

The first two mosfet is controlled by charging ic. If it is N channel mosfet (which most laptop have) then its gate supply should be approx 25v which is controlled by charging IC. If charging Ic requirement not complete then it will not 25v gate supply. If is P channel mosfet then gate supply must be low then source or drain. I am surely say that we should first check charging ic requirements. Hope for the best. I learned lot lots of things from your video. Thanks for sharing your most amazing knowledge & experience with us.

Hope you repair this board. 👍🏼

Hello there. I am a new subscriber to your channel. i love how you teach aspirant computer technicians such as my self. i know my comment is off topic to your video but im desperate right now. i am having a problem with my GPU. it's a Gigabyte RX 570 4GB. it's working as of this moment. When i tried to benchmark this it just shuts my pc off and turn it on. tried to flash the bios with a new version but it just freezes the screen and i need to restart it. What i did was plug this to other pc and still the same, i also tried repasting it,changing the fans,,i tried 3 working PSU and still no change ,when i set my monitors hertz to 165 it goes to 60 degrees idle, i also tried re-installing its driver using DDU, I've checked the board and there are no signs of burns. Sometimes the screen glitches out like the display jumps. i don't know what to do anymore. Yes i can still play games on it like dota 2 but in low settings. I also tried playing valorant in low settings and it works fine. Higher than medium settings it will shoot its temp to 89 degrees. This isn't like this before. i also tried going back to the previous version of driver where it worked before. i hope you or anyone have experienced this kind of problem with gigabyte GPU's and can teach it other aspiring computer technicians. thankyou! please ask me more question so i can explain it to you a little bit more on what is happening to my card. once again more power to your channel! liked and subscribed!

11:30 is that thermal paste or liquid metal? If liquid metal, thatd be shorting all those caps on the cpu.

@10:01 dont know if thats dirt or what not below the silver cap seems like it touching the other cap its prob just dirt know

I didn't see you checking for 5v or 3.3v after jumping the power protection, maybe that should give you a clue of maybe a dead super io or something similar.

It's cool that you posted it for community input instead of just calling it a no fix

hi Alex try replacing PM IC seems like all mosfet gate controller not functioning it could be pm ic or pch or cpu

I just had a laptop with a similar issue. I ended up having to replace both the charging port and the Power Management IC.

I would suggest you to check all voltage rails present in laptop

Did you get it fixed? IMHO the mobo was previously shorted and there is an open device, shunt resistor or current sense resistor. What does it do when the battery is installed and the charged is plugged in?

Hi at 4.16 is that a damaged component?

Follow the power sequence of laptop and measure the power good(PGD) value of charging ic. If it's missing check the requirements for charging ic.

Somotimes those eight timer chips come lose from the board because of heat try checking those legs.

you should check vin of the charging ic acdet line and regn pins

Is it possible an inductor connecting to that mosfet is weak or bad cos there is no short but the voltage is low, or it could be a Feedback Resister that’s bad!!!

Any follow up to this repair?

keep up the good work. l am learning a lot😊😊😊

please check from where gate voltage is generated and why it is not generating gate voltage may it is a fault of passive component or gate controlling ic is faulty

Alex I think ur problem is the gate drive on the mosfet is missing. The gate drive usually comes from the power controller chip . Thats my input

Seems to be a good candidate for immersion testing.

at 10:07 in video there was a solder blob looking object between a larger cap and smaller one. Maybe was a short there at some point?

Hello Alex sir. my laptop can't charge but cherging light is on. whole day plugin but onley charge 12% after opening the laptop still draing battery not useing AC power what's the possible cause for this problem. it's a ASUS s510uq. i hope you replay me.

Give the first two MOSFET are in effect a reverse polarity diode....with 19 V across the first one....gate drive is missing.....and what provides this " 20" V? You speak of.....there must be a bootstrap circuit somewhere

May be it is one of the back converter problem +5v 3.3v especially the 1.5 or 1.2 v

when you dont have the 25+v on the frist 2 mosfets is because the charging ic is not working, you need to check the battery charging circuit and check the chargin IC, it is the one that send the 25+v to the first 2 mosfets

you have to cheek charge ic and its circuit because the charge ic if works will give the too mosfites that you take them out the gate to work

It will be good to have the board model, perhaps someone will have the schematics for it. For sure it would not hurt. Thanks for the video.

Nice video Alex!! Tell me, why do you wear gloves when doing some repairs?

It could be a crucial component is missing from the board that's not allowing power to get through.

What termal are u using?

learn daily somthing new big follower sir RESPECT.

I love that always get asus ads for these videos

Hi you might want to start by resting the bios by removing the internal battery (BIOS Battery) then shorting the battery terminals on the motherboard for at least 30 seconds. I might sound silly but modern laptops have a tendency of freezing BIOS

Can this be a bios issue?

Check 3.3v around small caps nearby superio ic.probably bad sio.if not then needs to check voltage regulators

Change both mosfets that you took out, the problem is one of the is partially shorted that is why you have 4.8 V, i have found that problem before

Also like to add that when I opened it there was liquid metal spill on parts of motherboard and no mosfets check shorted.

hello, watch your video at 10:05 between the 25v capacitor and the SMD. That might be the source of your problem. Cordially.

Looks like there has an issue with PCB connections which not passing the power to next components

Retimer? Something telling the board that it has proper voltage, blown mini fuse some where, grounding plane for the power supply sometimes gets janked because of dropping while plugged in, reflow the charge port

What is the name of this motherboard?

I'm a Newby but I would change charging ic or a resitor issue around charging ic

If not getting 25v on the gate..something must be wrong with controller...check the vcc or vinput the controller.