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(10:06) I would proceed like this: 1.- Verify that there is no very low reading or short circuit on the terminals of the ceramic capacitors connected directly to pins 2, 22, 23 and 29 of the TPS51220A IC. 2.- Verify that resistors R112, R725, R392 connected to pins 26, 3 and 31 of the IC are not open (infinite reading). 3.- What reading in Ohms and then in the diode test function do you get on pin 12 of the IC? Now yes, without hesitation I would replace the IC with a new one and repeat the measurements in the previous three steps. Thank you very much for your time and sharing. All the best.

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Nice review. Interesting to see how the circuits are different from HP laptops that I mostly deal with.

THANKS FOR REPAIR SHARING BROTHER

I plan to appropriate your "congregation of dirt" expression. That's a keeper.

Gratz for the amazing job done.

Nice one... 🎉

Excellent explanation. Just do more of this videos sir

Great job. Keep em coming

THANKS ! It’s nice of you to share your repair techniques ! 🤩

Very nice and helpful and educative

appreciate your efforts

I thought you were going to say that you found this in a sink.

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Where did u get all the driver ? Mine are alot missin i ran alot of driver programms it helped a little. I also disabled the ACPI driver but now it didnt show me any "battery"

Excellent educational content and video-please continue to create more.

(15:22 exactly) DDR DIMM connector (empty, where you don't have the RAM module) the corrosion is seen very close to the black plastic although the terminals seem to be well soldered to the PCB. If the other DIMM Connector is in the same condition, that would explain the zero (0) volts you indicate on the body of the inductor. Furthermore, a damaged DIMM connector and/or RAM module causes no image on the screen. Just to the right and also above the CPU (which has the exact shape of a square) there are two QUAD type ICs, I would extract them to properly clean the pads and then return them back to the board, that is, an attempt to see if the 0 (zero) volts indicated on nearby inductors change. (16:23) Totally agree. Put me in your place: “the fluctuation is killing me” (it has already exhausted my little patience)... damn. Okay, I can't take it anymore, I'll order new ones to change them. Thank you very much for the measurements shared (reference when you face another similar board). Don't put pressure on yourself when the content you show us doesn't have a solution when you present it because we always learn something. All the best.

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Looking forward to a 2nd video on this. Thank you for the content

I am so lucky that I have so many donor boards, but that is because I only work on two Dell motherboard models. If I needed parts for random faulty motherboards, I would be in trouble.

I wonder if it would be worth it in these cases to try a desktop graphics card just to rule out the laptop graphics card.... I've seen people here on YT use their graphics cards in laptops.

Great suggestions as usual guys. This motherboard is definitely coming back out of the rubbish bin, to try out the suggestions below!

Check the current draw, if it is constantly changing it means that your cpu and onboard graphics are most likely still good.

I suggest to check thr resistors near the GPU

nice way of explaining

I ve not seen any Lenovo laptops that works with the hdmi cable outside of windows.

I would put my money on the BIOS again. Did you check if the BIOS dump you used had ME cleaned ? Do you know how to do it ? There is a nice guide on badcaps forums. If you decide to do it keep in mind that you have to clean ME on the original dump not the one you downloaded from the badcaps.

I'd suggest connecting everything again, powering it up and leaving it; Some boards do take a while, and several reboots, to finish ram training after such jobs. I've had boards that needed 3-4 reboots, taking well over a minute, with on-off-on... Then it posts ;)

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A noble effort. I expected to see you put your finger on the PCH to see if it gets hotter than expected. I hope you got some beauty sleep to be fresh for Monday morning.

Hello. I have this exact same motherboard that isn't powering on, and have been following your steps. However, in my case, at 06:00, I *do* get a short between ground and after the second mosfet. Any ideas what that would mean? Sorry, I'm a beginner at this kind of thing.

@therepairshare673 Awesome 👌 Sometimes, it's the little things we miss, and we all do it! I can highly recommend getting a couple of the CMIzapper tools; Specifically the Chipmunk (both the USB tester and the HDMI tester). Having the USB tester can often tell you very quickly what's going on with a board, without having to do aything but plugging it in to USB port and pressing power button. I haven't bought both the USB-A and USB-C, only the latest USB-A (because I "tidied away" my original; I just use a USC-C -> USB-A adapter

I am in shock! (for good, that is, in a positive way). I would never have imagined that the LED would stay on when connecting an external monitor. I connect an external monitor when I see a dim and diffuse image (helped with the flashlight), that is, without backlighting and then I focus my failure analysis on the motherboard and also on the T-Con attached to the panel to check all the SMD components very close to the LVDS signal cable. Does the Super I/O IC detect that there is no display device (as a load) and stop the startup of the machine, in this case two from the manufacturer Dell? From what we see here: That's how it seems to be! I definitely learned something I had no idea about today. Thank you very much for your time and sharing. All the best.

Outstanding 🎉

Many dell laptops actually need a laptop screen connected to the lvds cable to post.Even a broken one,even the scalar board,without the lcd screen.

Thanks for the update. I really don't know this tip.

One of the best channels on CZcams. Thanks.

Listen to me: you’re one of the best. And I mean, among those Big ones that you mentioned in this video. Thank you SO much for what you’re doing.

(1:12) Check the inductors. (15:16 exactly) PU4502 you should reprogram it again. I am left with the sensation (impression or feeling) that you are one step away from solving it. Good luck. All the best.

I liked. It looks simple, so I would try it although I am useless for anything mechanical and mainly a car and I end up damaging it even more. Thanks a lot for sharing. All the best. PS: Because of what I mentioned above, I don't dare to face ECU (Engine Control Unit) even though I watched a lot of video content.

Excellent explanation

Most laptop LCD's have full time 19v (or whatever main voltage) all the time and if you misalign the LCD connector plugging the cable back in can cause a short. A blown fuse is the best you can hope for in this case.

Thanks for 5e knowledge sir

Hello. I am one of your Mexican subscribers and it goes without saying: I love your content and the comments of your colleagues. Due to the thunderstorms I had no power and heavy rain will continue today. Thank you for your kindness in mentioning the Mexican people. I will give my technical opinion as soon as I can. A fraternal greeting to all.

Great Videos and thank you for all efforts. I just have one question and please excuse my ignorance. P Channel Mosfets PU4201 and PU4402. The 19.5v goes through Source of PU4201 and out the Drain and Drain of PU4402 and comes out of Source. I really thought the current travels through the Source and out of the Drain which is not the case here?

Thanks teacher

I heard the beep! As Phil would say, "Shut up, multimeter!"

Thank you for mentioning at the end of the video that you tried replacing the CR2032 battery. It looks like an original factory battery, which usually measures less than 3.0V when out of circuit on the great majority of these older Dell laptops in my experience.

If you are confident that GPU and CPU are good, you can use thermal camera. Thermal camera is a very good friend to find shorted micro SMDs (especially the CAPS) If thermal camera shows heat detection on any IC, check the surrounding CAPS connected that IC. For a guy who debugs so many PCBs, require a thermal camera (which is used when all the hopes on a PCB is lost)

You mentioned that measurements for the bios chip Nu. 8 is 1.8 it should be 3.3 . Try to change the bios chip