I had a similar case on some Acer model as well. I had the same mosfet faulty ordered it changed it and it worked for like 5 minutes after the cutomer got home. Came back, it was another one of those CPU mosfets. I think once they fail and the ppl on discord suggested the same, you have to replace them all to avoid that thing where one is new and another old and tired and having different parameters. Answering ur question on what i would do is very simple. Do what it takes so that you don't have the next taught tomorrow: What if ? What If i changed the mosfet with the same one? This is how i go about it. No matter that i order a batch of 10 mosfets and its 50 euros out of my pocket and it doesn't work if that "what if" its gone and doesn't bother me tomorrow 😉

Wow you are a man of patience!!! I would have thrown it in the trash from the first failure!!!🤣🤣🤣

Don't feel bad Sorin. You've showed us several ways to find the hot spot and using a thermal camera is really the best way. If someone doesn't have a thermal camera, even a really cheap one will work. They have really dropped in price over the last several years. Using petrol or alcohol is always an option for those who can not afford a thermal camera at this time.

Hi sorin the ohms value is normal on i7 9900k . Newer cpu has under 1 ohm. That double diode you can find on every board. The no picture can be bios also , also some boards needs the biosbattery to give picture. I had once acer which was dead just because the bios battery was empty. That mosfet is common one which you can find on other boards too. To see if bios responding you can put and extern keyboard and toggle the capslock. And see if it reacts. On my opion you do not have a dead cpu. Also the coil who has no voltage is normal . It is the gfx coil comes up when the laptop is underloas. Per example loading windows

Thank you so much for videos like this. I learn so much from watching someone, who knows what they are doing, troubleshoot the difficult issues and explain various things along the way, which is something I haven't been able to find elsewhere.

S43 is according to an SMD code book BAS40C, Dual, Schottky, 40V, 200mA, Vf

Hi Sorin. I still liked the video because there’s lots to learn here. Thank you! I would’ve liked a more thorough explanation on how you found the 3.3V.

Hi Sorin, worth to check with an external monitor to exlude the display, but as you said most likely cpu is dead, i hope it's not one of those laptops that has to have battery plugged and fan plugged in order to start properly.

That has been really much Electronic Logic troubleshooting which really needs someone expert like you. I adore that for sure.

Sorin, to me this is a great video, even if it wasn't fixed at the end. Your 'no fix' videos still help with learning debugging of issues; thank you for this. I wouldn't buy a new mosfet for this, but when replacing the good mosfet at 13:30, I would have put it onto the first CPU power phase, since I've seen some designs (mainly on GPUs) that use only the first power phase during boot up. I'm assuming most CPUs can operate with one power phase missing as long as your are not running high load. After replacing all RAM sticks, have you tried powering it on and checking all voltage rails? P.S. As others have asked in the comments, please modify your multimeter to make the beep quieter, you are the master of fixes 😄

Thanks Sorin for the great Video, From the people of Sri Lanka...

Yes, I splurged and bought a nice thermal camera. I can’t imagine living without it now.

Hi Sorin. Are the multimeter beeps very loud or is the meter too close to the mic? It was quite uncomfortable to listen to for the last few videos.

Sorin, great troubleshooting. the MOSFET that you used as a replacement appears to be compatible with the original. I would not order a new MOSFET, but I would replace the faulty dual-diode to see if power flows again. I think you need to go back to the input MOSFETs again to see if 19v passes on the drain of the second one after the diode replacement. Otherwise, that needs to be resolved before you can call it a fix. Good luck!

Great as usual, after bring a life for MB reset bios and connect bios battery also try to connect fans Thank you Sorin you are the Godfather of this job forever 💐

Hi Sorin, nice video as usual, try to change 2 dual mosfet together from same type if they are in parallel just to make sure they are working in same sequence, further if PCH is mad hot then we have problem... I learned a lot from you, you are the boss

Hi sorin ,this is the best diagnosing video,learn alot from here to there, in Real time👍

I think the previous person who tried to fix this laptop, caused those others problems. Extremely high temps on PCH, dead dual diode, double mosfet on cpu power rail also dead... Too much failures on different places of the board. Its more than just strange. In my opinion, Sorin dont waste any more time on this laptop.. :)

Sorin, did you notice the spark? When testing the mosfet at 23:49. Yet power supply showed, no current draw. Interesting love your the problem solving.

doesn't matter Sorin that you did or didn't repair the item :) you tried :) but the fault finding process to diagnose the problem is what I like to watch :) laptop repair more than anything :) but I will watch most electronic devices you post to fix:)

I would also have tried the two memory sticks, one by one, in the other memory socket. What I saw earlier: 3.3volts became present on the keyboard ...... after you did 6 things. 1. You check for 3.3volts on the keyboard: no 3.3volts on the keyboard. 2: You FIRST remove the memory stick nearest the keyboard socket. 3. You THEN remove the keyboard ribbon cable. 4. You check for 3.3volts: its present. 5: you re-seat the keyboard ribbon cable. 6. You check for 3.3volts; it is now present on the Keyboard. I've had instances where memory sticks or memory sockets have been faulty.

Nice job, that is a no fix, don't waste any more time with it. As always you're skills and knowledge are great thanks for sharing.

sorin some acer laptops needs the cover in order for it to start and display picture. There is a switch near the ram slots that detects if the ram cover is in place. you might wanna check on this.

Try connecting the fans. Maybe the bios detects that there is no fan and is shutting down. I know it is a long shot but.... you never know.

Foarte tare ceea ce faci Sorin ! Felicitari pentru acest canal cu content informativ

I'm never the 1st. But I was watching your live from 4 years ago: Coffee & Electronics . One you help a guy to fix his electronics.

motherboard repair is not talk about result , but the whole proses and you do the the good from begining

Unless it is calibrated 1.2 ohm will be the probes resistance. It seems like a short circuit. Many ohmmeters manuals instruct to subtract the resistance of the shorted probes to the reading.

Hey sorin you have mind blowing knowledge about electronics but I never seen video on signal level repairing. You have got only voltage level problem. Don’t take it wrong 😊

The cpu seems shortet to me. 1,5 ohms is way to low, i think have to be between 5-15 ohms like most gtx gpus have. Two faults is bad, there was some work by others before on this laptop can be the reason.🤔 You can test the power good signal on the driver ic, if the mosfet is the reason or not the signal will be missing. Connect a cable to the signal pin and test that out, befor you buy a new mosfet. A few days ago I had a defective GMX notebook here to be repaired, one of the mosfets for the GPU voltage had a short circuit. The gpu was 15 ohms and I was sure it couldn't be broken. Unfortunately, the UP1642P driver IC was also defective, so that the fet immediately became defective again. I then exchanged both mosfets and the driver ic and the notebook ran again.

I think that the dual diode burned due to the high current draw. Those small diodes are rated for 500 mA, as far as I understand.

Before ordering the mosfet check with an external hdmi monitör and check for gpu section

Looks for me as a corrupted BIOS. I've seen many no picture laptops with that kind of fault.

Since August 2022 there is a free schematic and boardview of this board. There is no point in wasting time looking for components on the board.

Thank you Sorin, as always your videos are very interesting to watch, keep up your excellent work.

There's a voltage control in the bios, and there is commonly heating issues on this laptop.

I’m thinking connected the FiOS battery would have helped, and just like you said ordering the chips would be helpful to eliminate a variable but I’m not an expert

Hi Sorin, a lot to learn from this video, thanks a lot. My modest opinion? No, I would not order the mosfet, I understood it is expensive while it is verly likely to be a dead cpu, statistically speaking. In addition, as you tought us, from camera the cpu showed heat from a point and not uniform heat... We’ll wait for you decision. Bye!

3.3valp @ pu301 according to the schematics.. +3vlp must be present. For econ.. then +5valw will be enabled by ec.. Check pin 14- feed back for voltage.

Great video master Sorin! I am not a professional and from my prospective, this repair is way too hardo to fix..you did propbably the same what i would do...but at this point i would probably stop since this is probably a dead cpu or chipset.

11.00-13.00 I could see burn flux under second mosfet to know that this is a faulty one, it is a very known sign of a bad mosfet

43:00 - Search "s-manuals smd" then u get chart. S43 is PBSS4350X, its NPN transistor. Datasheet is there also.

Another approach: In the area of the CPU, this device obviously gets very warm, and also asymmetrically from the side where the mosfets are located. With appropriate thermal cycles, I put the possibility of broken / black BGA balls in the room...

Scoring don’t worry about using thermal camera. You can just explain people could use there fingers to find the hot spots an then use the alcohol method you use

50:21 nice memories Sorin. :)

actually the integrated card on the newer systems isnt on the chipset, its inside the cpu itself, but if the chipeset is getting hot its not a good thing

I knew it I knew that you're going to be using a proper calibrated fuse in a 1+ hour video hehehe not disappointed worth the watching

Tq sorin sir for making a good video like this it's very helpful to learn to gain method logical thinking

ofcurse you should order the mosfet ..if works great if not you have a stock of it for another future job

surely double diode is a bridge with sio to detect shutdown but is now shorted and chip management on and cpu getting hotter

can't win them all Sorin, what does your instinct say and listen to that..yes your right lot learnt from this tracking the faults and backtracking i'm personally starting to learn functions that a year ago i just drew a blank stare when looking at a dead board of mine dell studio 17" laptop with so many chips and what are their functions.

I thought a scroll wheel on a mouse was useless, that's going back a while now, until I got one with a scroll wheel. Now I can't live without a 5 button mouse AND THE SCROLL WHEEL. It is much like life without a thermal camera until you get a thermal camera and then life is not the same without one. **its because productivity has gone up a level.** Short circuits that don't even seem warm can now be seen.**

I’ve the same problem same board /laptop, countless checks done, tried the USB reflash method Fn+Esc but no joy, customer said it stopped working after Win11 updates, but his MATE took a look so it arrived as a jig saw… so tomorrow I have the BIOS programming kit coming will flash it and let you know how I get on.

i must say i always learn new when i c ur video ....thanks very much

Great video! I would plug in an HDMI cord and try to see if you can get output display through that channel.

Nice one Vince...

Thermal camera is not a wasted money, is an investment for whoever works electronics

Maybe try with battery of bios, or reprogram bios chip and different ram.

Try check if the bios has been corrupted. Can happen that the owner had performed at bios update and it failed. In some cases you have both a EC chip and a Bios chip, if one of them is corrupted or they have 2 different versions you will get all kind of different issues. I had a Alienware where a bios flashing had gone wrong and it was completely dead, no light, no 3.3v, nothing absolutely stone dead. I used a ch341a programmer and flashed both the ec and bios chip and it came back to live.

Hi SOrin great vedio I learn alot but just to add you could used extrenal display to exclude the display also in these mosfet power rail shortage senarios the bios cheip get corupted and need reflashing .

Nice termal Cam.

PD81 is a double DIODE for power entry of charger AND battery (not ground)

23:48 you applied voltage at the output of the first mosfet,and i saw a sparklight,but no amp in any of your instruments......so, is your instrument too slow to saw us a a fast amp drawn from a possible capacitor-s? or its something else?

0:20 - wonder if the i7 sticker was that crooked from the factory. Probably not, but it seems that almost all laptops come with crooked stickers for some reason to the point that people often joke about it.

Dont feel bad i need it too

Hi Sorin! I would try with an external screen just to see if it’s any life in it. Thanks for your informative videos

Hi, can you tape up the buzzer on your multimeter please it's so loud 📢

An Asus laptop battery made a burning smell when I discharged it in Bios, and it reached 50 minutes. The battery became better, was capable to hibernate at 1%.

Thank you

Don't feel bad. You have a thermal camera, use it. :)

hi sorin ,im enjoying your videos , what e-juice do u prefer by the way ?

like a doc !!!

Voltage on the screen is okay? Normally you check that there is no light at all and I think you did do everything good Now check it before ordering. You must see some light on the screen I mean no picture but it’s on or not

its dual diode one voltage from the battery one from the 19v

I belleve mr sorin can fixed thanks for good video.

I would check if the lcd is working as it should!

One thing about your multimeter on resistance mode does it show the right reading when you short the two probes mine is really dodgy on the 200ohm range it gives me random readings i have to adjust the knob until it's stable otherwise some low value resistors will show open but they're not

Hello Sorin, I have the same laptop with faulty mobo... The service in my City said that pch chip is Faulty... I dont believe to that. Im guessing from knowledge from your clips its faulty mosfet or something less complicated than PCH

I learned allots.

Nice one, but try to replace the exact MOSFETS and diode

oh here comes the true story of the proper calibrated fuse 🤔😂

I Think We/You Need MORE "Dodgy" Wire 😂. Where can we get some ?!

I came on the same result on a very similar laptop (helios 300 i7 10th RTX3070), i was hyped after replacing the first power rail Mosfet and after removing a shorted cap on the 3V3, It bring my laptop to the same state. Unfortunatly, i think that i have accidentaly killed the CPU when the containing box falloff, the heatsink has made a small scratch on the CPU cristal :\. i can not felt the scratch on touch but definetly visible after cleaning.... I had no luck as always :(

only dogs hate that sound 😅😅😅 just kidding

When many pair of hands get on a repair, it's a mess to repair.

hello, most probably ,this mosft blown during heavy gaming as integrated GPU is the default one not dedicated GPU,even if you change the mosfet ,will not post ,needs cpu reballing.

Fa un video in care arati cum incerci sugestiile din fiecare comentariu. Ar fi f interesant. Bipul de la multimetru strica auditia, mai ales in casti.

Sorinel, am observat o schimbare la 180 de grade de cand ti-ai deschis propria firma...tipic romaneasca. Aparatura moderna?? Camera termo?? Manusi negre?? Ce s-a intamplat intre timp?

In your Web browser (your internet browser, be that Edge or Firefox or Brave), and add an adblock extension and remove the baltent unwanted advertising that poisons your internet experience.

Your screwdriver has a ratchet? The link points to a different screwdriver (I have it) that is woefully underpowered. Where to get the exact one you have? Also, curious why you didn't test with external monitor? Maybe LCD is dead?

Replace mosfet... there is a controller looking for feedback from that rail.

We want you sir to dedicate a video to a problem about DC jack power. laptop latitude e6410

I had one of these that would start with my power supply even though it had a partially shorted first mosfet and a shorted GPU mosfet. Luckilly it finally died while i had it apart and i foundband replaced both mosfets and it came back to life. Do we think its a mosfet driver issue? Shouldn't I burn it in for awhile to see if it dies again?

I like you videos thankyou, probably the chipset is shorted in side .🙂

When the keyboard light up i was hoping to see a picture on the screen too bad after what you did, i have an asus laptop with similar issue it has a dead battery but it booted just fine with a charger and i could access windows 8 then right after a windows 8 update and hdd repair i got a blue screen of death i left it for few weeks than turned it on it shows a black screen even on an external monitor so bios is unaccessible, wifi led stays on and fan turns at high speed it could be the pch, the cpu or the bios i have no idea i still keep it

hi.whats ur electric screw driver mark and model and retail price?

'Littlle Chyrnoble" .. Hilarious 😆 (great name for a mosfet company) 😮 !?

Have you tried pluging BIOS battery? One of mine didn't start befor I change it, and it was low on battery, 1,8V

Please order 👍🙏🏻

I think the S4XX series are double diodes.