Acer chromebook CB3-431 screen replacement, no backlight

[@klwthe3rd]

I only wish I could be as successful as Sorin when it comes to fixing electronics. I have so much respect for him that I watch every single video he produces. I always smile when watching his videos because he is so wise to know to order by the number on the screen, not the model number on the computer.

[@abazlezha7168]

Po

[@abazlezha7168]

Për të populluar dhe të përulur real anisa

[@abazlezha7168]

Qendra duhet të vendosë te të cilat e mbrojnë domenat dhe cakalli mundim mund përdor edhe edhe erotike kjo është kjo është elona 242 gjithate në politikë kur doli në

[@abazlezha7168]

Në rastin tonë senja tiranë por emëruesi tri komuna brigjeve k doktrina

[@neelbanerjee3086]

sir you ar happy to know that i used you technique to resolve the backlight of a Dell laptop the led enable signal is missing so, I provide 3.3 volt to the LED en.and the laptop works fine. thank you so much. love your videos keep doing. stay safe in lock down. lot's of love from india ❤️🤗

[@charlieandrews2873]

Sorin, You have a true gift my friend & its your captivating teaching style, you put us the viewer there with you your able to talk to the camera the way you would talk to a student in front of you. the way you say "sorry you cant see" when you know we cant see what you see because the microscope out of frame Thanks mate for doing what you do, your a "proper good" bloody legend, Greetings from Australia :) Charlie

[@ambersmith6517]

truly gifted

[@appiahishmael5340]

Nice video,I don't know anything about electronics but through watching your videos I have fix a lot of laptops for myself and friends,thanks a lot and God bless you.

[@swahilitech2024]

From Tanzania! Thanks Alot Sorin, Next Month Im About To Open My Own Repair Shop Based On Your Knowledge

[@PS3RatBag98]

Good luck. Let us know how you get on

[@jpius1017]

Funguatu mzee baba tuje

[@nisaprotv5866]

Hahahaaa upo wapi mzee?

[@jpius1017]

@@nisaprotv5866 nipo dom na mcheki sana huyo jamaa yuko vizuri

[@nisaprotv5866]

Yah yuko vizur sana... Mm pia namfuatilia sana

[@DavidA-411]

The problem was that the screen brightness was adjusted to a very low setting. This setting is saved in the I O chip. When you added the 3.3 voltage you reset the brightness level. Great deductive work.

[@TurboTechieSystemsIrving]

I had this problem with a Lenovo laptop last week. Jumped PWM to the 3.3 Enable and the laptop now has backlight and works perfectly after like 40 reboots. Guess it resets the chip or whatever.

[@terryhill6935]

Mr. Sonnin, I’d like to thank you for doing what you do, it means a lot to me..As you said in one of the beginners video, which I’m very much a beginner, your trying to reduce 5 years of going to school to 20 minutes (pretty funny, and true) ..I’ve made the phot sensor, made the liquid flux and as I mentioned on first comment the homemade hot air gun..(need much practice)..going thru the fundamentals of electronics is extremely helpful and I hope you continue beginner videos...Audio equipment is what I like and am currently working on an old ADC equalizer which the first thing I did was burn a pad out..I did a jumper, and really don’t know if it worked as still no lights come on, on one side of the equalizer which is a 20 band equalizer, so 10 lights are not working..proper grounding techniques would be cool..If I ever fix it, I will owe it all to your videos..

[@digihorse6730]

LED_PWM, I read that as pulse width modulation. Are you sure it wasn't that the brightness was turned down and you putting the voltage on it causes it to rise and remember the brightness setting. PWM being a pulse train that adjusts in width to give brightness level.

[@Radek__]

Exactly. If you put 3.3V on led_pwm you will get full brightness. There is nothing wrong to put there constant 3.3v without any pwm, but If you put pwm signal there you will get dimmer picture depending of pwm type. So you can do a jumper wire from any other 3.3V to that pin to keep full brightness. The only one disadvantages will be not working brightness regulation in windows (as Sorin said). And of course if you do it, then better cut the trace or cut the wire to prevent 3.3 voltage goes back from your jumper wire to motherboard.

[@armunro]

Agreed pulse width modulation. You flipped it up. Maybe removing CMOS battery and main battery would achieved the same thing. Firmware shinannigans.

[@dogandhunterphilippines4644]

Nice teacher because as i know the teacher have to discuse and you have give a student problem solving thanks man because 1 out 10 people they have not share her knowledge im proud to be your student

[@loverboy8273]

it is a classic, you opened a closed/stuck gate with the voltage feed

[@davianceable]

Yeah stuck gate switch opened or super İ/O thought there is some problem in baclight and cut the led voltage for further damage than it gets back to normal when voltage comeback!!!

[@djscratchmasterdee]

in my experience, some laptops even ipads and iphones need some kind of hard reset sometimes when replacing screen then backlight comes back to normal, took me a long time to figure this out, but it works everytime unless water damage .

[@djruido1]

Scratchmaster Dee I have an iPad I haven’t use because when I replaced the screen it did the same, could you explain a little more on how to do a hard reset on iPad?

[@loller7477]

@@djruido1 To hard reset an iPad you have to smash the screen hard a few times with a big hammer.

[@djscratchmasterdee]

@@djruido1 Make sure ipad is on and you can see that there is an image on the screen by using torch, make sure it is booted all the way to the password screen, dont have to enter the ipad pass the login but just have it on that screen, if you see no image, then you have a different issue. If you do see image, great, now do the following steps, also you can google ipad hard reset. 1. Hold down the home and on/off buttons at the same time. 2. Continue holding the buttons even after the slider appears on the screen if you can see that, continue holding and dont let go from step 1, it will turn off, then on again fews seconds after with backlight and you can let go. If this didnt help, then you may have other issue, bad lcd, cable no good, connecter no good on the board, backlight power rail failure. most of the time this works. Do let me know if this helped.

[@garypreston266]

you unfroze the chip a wee jolt of power iv seen this on a few of your repairs your just a lucky man anyone else would have blew the chip

[@yannis92preloude]

Lucky . On my own HP amd laptop I had screen But no pwm pulse Had to change big m- board ic. then all back to 100%. you can easily do a quick fix but you will have control on your brightness. Good job Sorin.

[@HITMAN111ALG]

GREAT VIDEOS ALWAYS .SIMPLE WORDS SIMPLE EXPLANATION EASY TO UNDERSTAND. we are waiting for more and more i wish you all the best mr.sorin

[@adryscoty4926]

Salutari si de la Timisoara Sorine,te urmaresc cu mult drag cu toate ca eu repar chiestii doar asa justfun, dar ma ajuta foarte mult postarile tale si experienta ta.Ai tu o asa o carisma aparte .Te salut cu stima si respect,tine-o tot asa si bafta multa.

[@Dheazzo]

I have a feeling there was a discharged capacitor on that line after supplying 3.3v externally then it charged up and current started flowing normally.

[@eliasbourozrrrs8585]

Master Sorin,good job as always.

[@titomar6634]

thank you so much sir. u help me so much when i troubleshooting in my net book. i never experience in repairing laptop/netbook before. i always watch on ur videos then learn so much. now i reapaired 2 laptop. may u continue in sharing ur knowledge.. 😏

[@luci295]

Sorine esti belea ! erai bun la electronica de cind eram mici ,ne-am cunoscut la cercul de electronica in Fagaras, ai venit la mine acasa pe Trandafirilor si mi-ai construit primul emitator ha ha ha. Te urmaresc de ceva timp si imi pareai cunoscut si nu stiam de unde te stiu. Continua asa ! Ma uit in fiecare zi sa vad daca publici ceva . Te salut !

[@redaalsbagh_9348]

Watching you while having a dinner. Thank you

[@AmerRimireZ]

hhhhh me to

[@Tomtech29]

as written below" PWM being a pulse train that adjusts in width to give brightness level. " you missed checking for changes in brightness and it works fine(Fn)+ F4,F5 or up and down arrows. very nice issue +++

[@mihaicatalind]

Stiu ca esti Roman ca te urmaresc de foarte mult timp. Esti genial! Totusi, incearca sa omori ticul asta cu "yea" ca suna ingrozitor si e iritant! Keep doing what you do !

[@garysparks2681]

The brightness was turned all the way down when they replaced the screen. That's why it came on brightly when you applied 3v. You should have put the old one back in, and it would have worked too.

[@googacct]

It might have been worthwhile to probe the PWM line with the oscilloscope to see if any signal was there. If it had reduced amplitude the voltmeter might not have detected it properly.

[@philipchinedu3287]

Amazing insight....... Enjoyed your videos as always.. Remain blessed sir

[@Madrasamisbahul-uloom]

Let's check togather is a feeling like i am working with him... 😊👏

[@andrewmcallister7781]

The PWM could have been shorted to ground (in the chip or motherboard somewhere) and you injecting 3V3 blew the short. If it was the PWM driver chip, it might mean that you have blown the PWM transistor pulling it to ground inside the PWM driver chip. A way to check that is the check the PWM signal on an oscilloscope or try adjusting the brightness down and if the LCD brightness doesnt go lower it is now stuck on full brightness

[@ayoubhamd-ellah1386]

I have a laptop with the same issue and i fixed with the same way

[@jameslancaster5335]

Yes, pwm means pulse width modulation which will vary the brightness of the screen. The activation of 3.3 volts started the pulse to widen which varied the brightness of the screen.

[@interestingspagetti]

Hey Sorin. Been a while since i last checked in on your vid's. Great channel my friend ;)

[@zx8401ztv]

The man that swapped the screen must have hit the screen off key, the Pulse width modulation test point was at zero, you applied power to it and the shock must have reset the pwm driver.

[@thembaningwenya1620]

100% correct

[@stevenszockson6868]

Awesome, I wish to be like you, you just fix things as if they are nothing.

[@preethamkumardh1115]

Your happy that "it got fixed". I know that feeling ;)

[@MrRvdbeek]

I like the magic you have done ✅ You are doing great i now how it works. Great explanation that we need all the voltage to have the screen working. Thank you for the video.

[@n3o325]

Yay, another video, another lesson. Arigatou gozaimasu, Sensei

[@PHONE-LAPTOP-REPAIR]

another funny and enjoyable and very very nice tutorial sir

[@kymcainday6677]

I wouldn't check the Led_pwm with voltmeter because the voltage will normally vary depending on the duty cycle of pwm. Instead I would use frequency tester (hz) to see if it's really running at intended frequency. The boost converter for led supply is actually controlled by pwm signal, and the voltage output that controls the brightness of the led can vary by changing the duty cycle of pwm signal.

[@DoomSlayerPT]

Thank u sir . ive learn so many with u . also u explaine !. thank u very much for share ur knolage with us. i was able to fix my dead toshiba motherboard .

[@paolog6998]

thanks for the video. Do you know if the chromebook acer 714-1w haw the emmc removable or soldered?

[@melchortungol4019]

you awaken the sleeping voltage hahahaha...Sorin is a good teacherrrrr hahahaha

[@martijn4740]

yep led pwm is deffinatly the lcd brightnes control connecting it to 3 volt just gives it full brightness

[@knightwar3]

Great save

[@RepairLap]

i confirm that , nice work . all what you need to do is Just puting a short circuit between LED_PWM -3.3v- and LED_EN . Note : does not mean a faulty panel or a fault motherboard is a question of compatibilty . .

[@RepairLap]

@@danielsatko- we will learn from you if you have any suggestion for that problem .

[@davidmcniven3543]

Hope it doesn't turn out to be an intermittent fault. I always hated it when I couldn't reproduce the customer's reported fault. Having magic fingers can be a curse...

[@charlieandrews2873]

So true David, it helps to know what you did

[@Labyrnthdom]

Yay another video.... At work watching :)

[@Mecano.r]

Thanks for the good video, i think when they replaced the screen they pushed the bright minus button to low and when you put the 3.3 there you kicked up the capacitor who is connected to a mosfet to maintain the brightness...please tel me if i'm wrong?

[@Dr.muthanna]

I know that you are magician had the touch of wizard Big thumbs up

[@ScouserStreamz]

Hi buddy only just stumbled across your channel before the vids you do and the way u explain is brilliant what is the power supply u use for your testing

[@TheKetsa]

I always order screens by the screen number - never had a problem. You need to remove battery and power when connecting/disconnecting screens or you risk blowing fuses. Happened to me on a T430 Had to completely disassemble it to find the related fuse on the back of the mainboard. My bet is brightness was set so low... screen had no backlight.

[@zngdrive]

Exact cum a spus si colegul Digi Horse, LED_PWM nu este led power ci led_pulse width modulation. In concluzie si eu cred acceasi treaba, in momentul in care ati venit cu 3v sa memorat valoarea maxima. Exclus condensator in scurt dat viind faptul ca erau doar 3v si curentul dat la minim sa arda acel condensator in scurt. Oricum un material bun si educativ :)

[@johnoddvar1967]

Some forbidden situation somewhere. If the foult dont come back its nothing to worry about. Great Video. What will u use to clean the screen if its dirty?

[@evilspeech9697]

Hi GrandMaster, thanks you for teach us. Do you know where find BIOS dumps for programming laptops? A lot of pages have ones, but is so expensive.

[@behzadsaboonchi]

nice repair 👍👍👍👍

[@shakaitadekunle5470]

Many thanks for the wonderful tutorials. Really interesting. I need help on tutorials that's based on all components of the motherboard. PDF materials that talks about it maybe helpful as well. Regards.

[@BreathYouTake]

i love your every video. im your big fun

[@elenamarinca1184]

hello It was happend , like some devices ,have the brightness off or at minimum, and given the impresion that is a BGA problem, but not.I think, that when the brightness control circuit detect current flowing, he set the brightness to this level.All the times in almost all the circuits, exist a current control, or a sense rezistor, which inform the IC .This was Marcel opinion...

[@khalkhal2372]

Nice and instructive video as useual

[@Ty-vr9cd]

Yeah...pwm pulse width modulation signal comming from super io..via resitor buffer..maybe static zap.. super io stuck ? Thats weird.. normally i find pwm and or enable comming from super io dead then requires a dodgy bypass to a 3.3 volt rail orchange super io...

[@buttertoast4189]

what was the tool used to to charge the LED?

[@COMPUTERREPAIRSCHOOL]

Just your magic touch 🥰

[@bilalsoltan8688]

When he tried to change the screen he caused a short so in the super sheep there is an internal block or sweetch to protect it so when you plug the 3.3 v you refresh it this is what hapoend thank you

[@abdelilahachtiouy2682]

Maybe was shorted by a cap. Then when you injected voltage the cap burned. Then the short gone...

[@ictrepairs6963]

You can’t burn a shorted cap with such a small amount of current...

[@TheRoadrunna]

This time petrol wasnt needed just amps and you fixed it.

[@agutek]

My guess is your colleague didn't actually remove the battery and when he replaced the screen and Super AIO protected itself by cutting the power down and what you did with your power supply was basically a reset. Just a guess, I have replaced a screen few days ago with the battery in and there's no backlight anymore, haven't looked at it yet but I'm curious if it's exactly the same like on this Chromebook.

[@electronic7979]

Useful video 👍

[@ciprian4760]

20:46 nice one Ha ha ha :) Nice job Respect

[@gile849]

Maby is be ok, only adjust from keyboard set to zero. Look when adjust, he going to zero light. 25:09.

[@Mark-sq8mh]

Hi guys. I didn t understood why motherboard can be damaged in case of screen replacement while power or battery is plugged in . May anyone explain thanks.

[@Radek__]

my answer for where was a reason is: Look at the screen cable at 13:38. Do you see how that plug is looks like?. Protection tape is broken. Plug is open - you see a lot of small cables. SO that guy BEFORE you Sorin - unplugged screen cable without precision, holding all cables and pulling them too fast, instead of pushing only the plug on metal edges. So I bet that one small cable is now broken inside or has bad solder connection pin in plug. You've put 3.3V and electrical flow temporary fix that connection or broken cable. Now it is working fine but we don't know if it will be after messing around with that screen cables or after disconnect charger and main battery and wait 2-5minutes. Maybe then that issue will comeback. That is way it is good to check if power cable is good - by checking connection between screen socket and motherboard socket and during this you shake/play with the cable. In this way you will have sure if the screen cable is good or bad. BUT you know about it. I'm explaining it only for those who don't know that.

[@jimmclaughlin1065]

I tend to agree that either a poor connection or a cold solder joint in the circuit was the problem and still may be. Over the last 40 years, Have seen similar incidence on Aircraft write ups that could not be duplicated after flight but repeat intermittently. Of course with these large wire runs we could generally find the problem with a TDR ; which isn't possible in a computer or close inspection for recessed pin. With luck it will hold together through your warranty period. Injecting the voltage could also have caused some sort of reset in the logic which nowadays qualifies as FM repair (F__king Magic) IMHO

[@omousek]

Hello I have a question. I can't find a schematic on lenovo yoga tab3 model: yt3-850m. The tablet was damaged by water, the oxidation removed by lcd flex not affected. thanks to all for your help

[@weerobot]

The Sorin Magic Touch strikes again...

[@DoomSlayerPT]

i have another board no power no light , also the 19v on charger its ok but when pluged not even directly from de pins ..it only give 1.5v and mosfet hot. i replaced the mosfet. and its the same . but without the mosfet no short to ground. what can i think abaut this :(

[@ISMAIL-dl3gw]

sir firstly you didn't try before to move up the brightness " May be the brightness was in the zero" and you know when we move up the brightness in same moment we was move the voltage

[@Franksxs]

it happens!

[@aaronrepairs9516]

you are right,,,maybe it was the case.

[@gerhardpetersen]

My thoughts too. Didn't try brightness up first. 25:06 screen dim, press bright and presto!

[@danielli6648]

The brand logo is also off so that is the case

[@faceitAvi]

Hi sir my laptop lenovo thinkpad which has samsung ltn141bt08 display and get white display problem can u provide a solution of this

[@is07tia]

Hi,unfortunately cant find button to send a pm. I have an acer with a power problem. Without battery,plug in to main ,push start button,fan starting,dvd writer starts for that start check but hdd does not start. I need to plug in and out several times to make the laptop to start. What could be the problem? Tested with another charger and same thing. Multumesc :)

[@ruudodekerken4350]

Amazing fix . Great

[@terryhill6935]

Mr. Sonnin, I would like to ask you about voltage supply. I watched your video oh how to make a homemade hot air gun..The gun I made is fine, controlling voltage,..A voltage regulator supply...I need help with..My house outlets are 110volts..Is there a video you have showing how to make this? Maybe I’ve missed it..I’m just watching your videos because it gets so confusing..I’m stuck..Hope this makes sense.

[@ahmedbellil5161]

can the IO save the last voltage value some how !!!! i mean how can a laptop remember the brightness !!! deam now we have burn a working laptop to make sure what happened

[@petarpetrov6388]

Thank you VERY much!

[@theultimatemyrmidon7459]

You always lucky Mr Sorin.. I am the only one to have several problems at the same time? Several shorts

[@paul-c7541]

What crossed my mind a stuck or lazy gate ,on the voltage side, what would I know I'm a TV man :)

[@xiMoshyx]

hi i have a different problem i have a blown 2r2 inductor does anyone know where i can source the part? or the actual part number please? thanks

[@johnloydcruzz5733]

do you repair tv / lcd led sir? thank you

[@عمارالراجح]

استاذي الكريم لك كل الشكر عندي سؤال لو ان المشكلة في backlight كيف الحل واذا فيه فيديو

[@lobotodabobo]

What multimeter are you running nowadays?

[@nostamine2567]

Am o intrebare, te rog sa nu razi :))) . Din greseala am masurat cu modul dioda pe multimetru o rezistenta prin care cred ca trecea curent alternativ. S-a ars rezistenta multimetrului si imi arata mereu 1 . L-am bulit sau pot sa ii mai fac ceva ? :)))

[@learngamecheating]

what if a capacitor is shorted to ground from both sides, i removed the capacitor test it was working fine but it's place on the screen pcb is shorted to ground from both sides

[@maseratimastare1849]

hey sorin love u channel

[@agecomputers2422]

I'm having problem with hpG4 motherboard 3.3v is present in sio and power switch not present in bios chip so laptop did not power on any body with good idea please.

[@onderol]

SCL and SDA pin ... i2c? can we drive this screen width arduino?

[@JVFIXLLC]

I don't know if u had I similar problem like mine, I have an alienware 17 laptop and the graphics card is upgradable. ok short story my screen supports 120hrz refresh rate and I can set it to 60 if I want and my issue is that my graphics card is a gtx980m used to work with 120hrz enabled but now it won't and it only works in 60hzr and it's detected in device manager. any ideas would be apreaciated thank you.

[@indiawest2025]

Reset the bios ,unplug the CMOS circular batter and update bios software

[@JVFIXLLC]

@@indiawest2025 I did that already man and it did not work.

[@indiawest2025]

@@JVFIXLLC try giving it another attempt that should fix it, wired. it normally takes multi pull trys.

[@indiawest2025]

Maybe try it with the gtx980m graphics card disabled, and the enabled

[@JVFIXLLC]

@@indiawest2025 ok I'll give it a shot. My original video card was a 780m and I upgraded to 980m and I been using modded drivers from Eurocom

[@rifatahmed4659]

I think brightness was zero at the beginning when you pushed voltage on pwm test point it increased brightness

[@paweepko6178]

I found such comment on the internet: "The inverter is designed for an RF impedance, not to drive into a simple DC resistive load like a multimeter, and I wouldn't be surprised if that voltage test has ruined more than a few inverters. " Can you explain me this?

[@paweepko6178]

On your videos, I see you investigating a living inverter using a multimeter. I would like to know if we can damage "living" inverter board by touching the multimer needle to the wrong smd element? The problem is described on this website - www.fonerbooks.com/test.htm

[@GalaicoPortucalense]

@@paweepko6178 this case is not about a screen with CCFL lamps but LED´s, generaly we call "inverter" to the tecnology used to light high voltage CCFL bulbs and in this case we have a driver LED and not an inverter one

[@davidjohnvillamin]

I think it just need to reset the superIO chip or the chip that handles the back light . And it has been reset when you put power on the screen. Sorry my English is very bad

[@peerapongs.3548]

I didn’t remove battery when unplug screen connector. It go wrong now power on and off suddenly it’s damage which component ? Anyone have a suggestion?or video that he fix it

[@benafluck]

You have a loose contact.that's why when you inject the voltage it came back alive.

[@oddity4650]

Yes that is what I was thinking

[@BreathYouTake]

sorry for disturbing you, i need your help. i have laptop was working everything ok but fan was dusty, i disasamble laptop took out motherboard and fan, clean it with 93% votka, alchohol.... after i build again, i used new HDD and write new windows, in installation stage was no working touchpad and i used extrenal usb mouse. after full install and drivers was all ok, no touchuchpad in device mamager, it seems he cant see my touchpad. but my touchpad is lighting. laptop model is hp dv6. with i5 second gen.... thank u sorin. help me if u can and i know u can. i checked voltages on touchpad connector and there was but two middle pins was zero... i can told u tomorrow more acurately and can take picture of this pins. it was dusty and i clean it.... didnot touch with anything....

[@kalaikarim4544]

Can an application called Desktop lighter help reduce the brightness. I use it on desktop. Please try and use it on a laptop with this problem where you can't change brightness. Hoping to hear from you that it works

[@jamalali101]

hahahahahhah it work some time this case done with me ( good work i flow your channel ) i work in hp company in maintenance laptop

[@leo.yi.martinez]

does acer chrome have power problems

[@ExtremeEngineering]

THANKS