Everything about the laptop backlight, LED Screen Voltages and Signals

[@RafaelAmorimmeu]

Honestly I should thank you very much for this video and this gentleman. I have an Asus Zenbook UX330UA 3 months ago with the black screen. I had already checked all the tracks, apparently burnt out components, damaged cables, power outages, after all, it was almost certain to buy another full screen. But after watching this video, I went to test the mentioned voltages (LED_EN, PWM) and everything was ok, but I remembered the fuses that he showed just before, and amazingly, when testing continuity in one of them, one did not whistle, success! Localized fault, fuse blown. With the multimeter on to measure high currents (10A) I connected it in series with the fuse and Voilà. The screen lit up properly, with my beautiful wallpaper, now just looking for a new fuse to replace. Thank you so much for sharing this information. It really isn't easy to find content on this level of quality hardware. You are amazing, I am another subscriber!

[@zXHAcKeRzXz]

My UX480FD-BE0 Has no backlight after some water incident and I brake the LVDS connector and soldering point by trying too hard to get it off. It would be really nice if you made a video showing your diagnostic and repair, because zenbook video are so rare

[@saarike]

This is really nice. I really appreciate people like you, who makes a lot of work to share knowledge about electricity and other stuff. There is very little information about that thing, witch you explained very nicely. Thanks a lot of these videos! :)

[@DasAntiNaziBroetchen]

@Taylor Benjamin Cool fake comments. Reported.

[@haimt]

thanks for tutorial , a small correction the PWM (pulse wide modulation) is not POWER but the signal to control the intensity of the backlight!

[@electronicsrepairschool]

Thank you, probably you are right, but i always bridge that one to 3.3v to get light on the screen. Maybe the day will come and i will finally have to read a laptop schematic :)

[@haimt]

you are very good without schematics , I am learning a lot form you tnx u very much!

[@electronicsrepairschool]

Thank you

[@Wuety06]

Uh... u sure about that ? Pwm ..pulsed dc is used to power leds all the time

[@thingshappen9199]

​@@electronicsrepairschool Hey Sorin i'm confused by some contradicting information you have put out there. If you go to 11:50 min in this video you said that on VLED there should be 19V however, when you go to this video kzbin.info/www/bejne/m3mkqqalrN1ppdk you mention that VLED is 3.3 V at 41:29 min. Please help me get this clear. Thanks much.

[@devil2005iscool]

The PWM stands for pulse width modulation. jumping it will mean the "mark time" is 100% therefore full brightness even if the user tried to dim the backlight using the keyboard. Good video keep them up :] I like seeing repairs from different perspectives. The difference between knowledge and understanding.

[@IsaacOLEG]

thanks for the comment, yes I was thinking that once bridged you cannot dimm led anymore. '(because of the "3.3v ) is it ?

[@shqiponjagv]

I really appreciate people like you, who makes a lot of work to share knowledge about electronics and other stuff. Thanks for this tutorial.

[@alaster33]

That's the Mars Element , working its influence ; thanks for showing up full of cold , you teach me so much , get well soon my friend

[@sinankuniyilathoot5188]

i repaired a laptop and and an emergency lantern because of sorin his vedios are great!

[@giorgostexnikos6976]

this knowlege is gold.thenks professor.

[@amuthan4137]

I am new in laptop repair though little experienced in mobile phone repair.in today smartphone PWM(Pulse width modulation ) singnal is generated in a 6leg light ic with direct battery voltage (3.7) and EN Signal from Power ic. In this section mostly the output diode or main supply gone faulty.thanks for your tutorial.

[@pettahprize6114]

Mr. Sorin , we need more & more lessons like this , carry on pls

[@Timpano_Francesco_Repairs]

Hi Sorin, very efficiente explanation on how the work the signal thank very much

[@masocco79ify]

You are a GURU of this... i appreciated all your videos about this issue. I Have an Asus Fx504 (gaming laptop) it has a backlight off. I tried all of your advices, change ribbon cable and led also. Voltages on led board are fine..19V, 3,3v Led-PW ,3,3V led-en. All Voltages on mainboard ALL fuseS, mosfets, etcc are WORKING FINE!!! But Backlight seems doest't work still. I don't know what can i do for repair my notebook! :(

[@ercost60]

Zdrastvuytye, moy drug! Thank you for this very helpful video on material not covered anywhere else, you make this stuff look easy. My Toshiba CL45 had no backlight, and after watching your video I found a blown SMT fuse on the 19V side and fixed it. Balshoye spasiba! PWM=pulse width modulation. Varying the duty cycle (% of on/off time) to the LED backlight controls the screen brightness.

[@MAXSLASH-f1b]

PWM mostly its a Pulse width modulation for lcd backlit Cold Cathode Fluorescent Lamps it is sending signals for inverter in your cause.

[@mrb3653]

Thank you so much for this video, gave me the confidence to attempt again to repair my laptop.... located the fault and now fixed.

[@albertalvarez5901]

Thank you sir for your video's another one for the books. I bought a Samsung Tab 2 with the screen having issues changing colors and weird lines on it so I remember one of your video's so I bought it and fixed it so easy...

[@azriamir3517]

Get well soon sir. Thanks for the great video

[@rashh77]

Nice tutorial. I hope you get well next time. Get some rest and warm your self and take something heal.

[@verdunelectronics9985]

hope feelin better nice video

[@plamenpetkov6958]

PWM means Pulse Width Modulation. By changing duty cycle on this pin we can continuously vary the brightness

[@knightwar3]

Thank you for sharing the diagnostic tips

[@PerrynBecky]

I have a laptop with a dead screen. I will definitely check it out with your tips. Thanks.

[@anselmomatusse6090]

Thanks for everything . You a the best teacher I know. I am technic for computer in Africa, Mozambique. If I need you help how I get you ???

[@z14t]

Get well soon

[@henriquepereira4058]

Pwm means post with modulation which is variation of voltages on with of a square tooth signal

[@saramatelot8322]

Thank you, helped a lot with my assigment!

[@komputel1]

bets regards from Poland pozdrawiam zajebiście tłumaczysz człowieku

[@travelinguganda7958]

Thank you so much sir, hoping to pay you a visit after covid-19

[@abisaiamatalo2769]

Awesome videos. watching all the way from Kenya.

[@pinakbhattacharjee7475]

thanks ... a very very good explanation ..the jumpering we also do but u explained it so simple.

[@adrianbullecer5749]

what a brilliant tutorial. very detailed. Long live to you sir!

[@revingtosh]

This is my new favourite KZbin channel. Thank you so much for all your tuition and hard work Sorin - it is much appreciated. If ever you come up to Liverpool - i'll buy you a beer :-)

[@sohailahmed6095]

Thank you so much my beautiful teacher

[@drrrw]

Absolute gold mine.

[@deepumullaka]

Thanks dear i have a short circuited lcd even though i removed those short circuit, 3. 5 was missing in led en but when i shorted that with pwm, the led eventually start up and 3.5 voltage was there on both points Screen was N156BGE❤️

[@pettahprize6114]

It is another very very useful tutorial for us,, Thanks so much ,, And also get well soon mr.sorin ....

[@electronicsrepairschool]

Thank you

[@yuanho2883]

Thank you! Hope you get well soon.

[@killitcam1324]

love the videos lots of good knowledge YA ! i lean from you many things YA (in russian accent) after i watch these videos man i always find myself talking like you YA lol thanks for the knowledge though much appreciated

[@TheOmerjaan]

thumbs up for a legend 👍🏻

[@ravindraadapa2952]

Hi sir I am very happy to follow you on your good videos sharing knowledgeable ones each have unique experience sir I'm having one question on this screen voltage can we check manually without connection between laptop mother board to confirm that screen is good or bad? Please clarify if possible

[@iv4nosky]

Thank you Mr.Sorin!

[@yuvarajan6678]

Thank you sir,your video very very helping for my knowledge sir thank you very much sir.......

[@paochitamanio8117]

very useful thank you so much

[@pradipkhairnar]

Thanks sir.. you explain complex problem so nicely..it helps a lot

[@dannytube474]

Hoping you are feeling much better my friend , Maybe when you went to Chafford Gorges Nature Park you caught something :)

[@viraldhangar5200]

sir very nice tutorial, sir you are explained very nicely.

[@ricanavarro9589]

get well sir.. dont die ok.. we may not see one like you to teach us.. thanks u,

[@electronicsrepairschool]

:))))) i will not die, i will survive :)))

[@dtech406]

In a situation where a normal current is in all the places, what do you check next week?

[@devanrajah9561]

You are my hero brother. Helped me outta a bind. Taught me so much. Thank you.

[@hexenkonig66]

Thanks Guy, you help me solve my display issue

[@dumezwenidube9952]

Thank you sir. Great lesson there.

[@JustJack99]

I don't have 19v, I have 16.8 and no 3.3 anywhere. What do I do now? I have image on screen but dim. Thanks, I loved this video... You are brilliant!

[@electronicsrepairschool]

check my video about backlight, is a easy job

[@interunkagain]

Legend right here!

[@RD-qp3mu]

Isn the PWM signal a pulse width modulated signal to adjust brightness by duty cycle, rather than analogue voltage?

[@samirzarour8562]

First. Very thanks. I have pv with no 19v out. I connect a 19v line to lcd point called VLED_IN. Now the backlight is ON but only when the charger is connected. When i remove charger. There is no backlight. What i need to do? There is also VLED_out... what is it?

[@vitobratta3937]

nice video and knowledge to share by the way if the screen no showing backlight can i jump the wire the same as you did?

[@electronicsrepairschool]

showing no backlight, but what about the picture? if is picture, yes, you can , after you check which one is missing

[@vitobratta3937]

thanks sorin i have the same problem showing picture but no backlight i take 3.3 volts jump to pwr led on and now screen have backlight thanks for sharing

[@tarkan06a]

thanks bro. my same problem and i only clear connector .. backlight working . again thanks

[@sadsea4285]

thank you ...really really i appreciate your help...thanks alot...

[@mamingujjar134]

What was the liquid thing that you used for cleaning? 99% alcohol? or something else? I am a newbie in repair school. I just started watching ur vids a few days ago. Thank you for sharing ur knowledge.

[@TheForexplanet]

I love ya man, you are a great teacher and you know so much.

[@bFABIO]

I need your knowledge!

[@rudiarta]

sir is that we need osciloscope to check like signal thing on lcd ?

[@jhaymhay1227]

Thank you so much, I've learned a lot to your video

[@pauliukasss69]

Also you should have around 32V on the LED light cable

[@shubhamahuja19]

sir can i use jumper from pin no 2..3 to pin no 4... because pin 4 voltage is missing.

[@xx3868]

Hi, i have a laptop screen suddenly stop working when the laptop is on and fans and lights ect and 1 amp draw at 19v -small laptop I checked at both the M/B connector and on inverter board and get 19V is that all thats needed to turn backlight on or is there a 3.3V somewhere to for text and BL ON? I shone bright light at screen and cant see any text- Nil and no light- Dead. I connected external monitor and Bios is showing perfectly and i can move around so computer seems ok GPU and CPU ect? How can both backlight and text suddenly stop? Arent they totally diff circuits OR need extra signals to turn them on even if 19 volts is on the little inverter board Thanks for any help

[@2doo554]

Hi! I have a lenovo yoga 500, the backlight on the screen it is okay when is plugged , but as soon as I remove the charger, I don't have backlight anymore...so on battery i don t have backlight only on Ac....what can be the problem?

[@domzzz1244]

Good videos, Thanks for uploading them.

[@mohammednawaz7222]

Tbh i follow all your videos and it has inspired me alot. Can you please show me a video of fixing the touchscreen issue in sony vaio pro 13 i7 laptop. Thank you.

[@viperdrake88]

Really enjoy your channel. I have a similar problem with similar device. Toshiba satellite laptop that has backlight at 100% brightness, any lower the backlight goes out or flickers. Replaced LCD screen (each came with an inverter) and also replaced the cable salvaged from another laptop. Also tried disabling the Intel HD power saving options and in power management, still having same issues. Any suggestions?

[@livancalcedo4626]

thanks for for the info you are a good teacher and electronics repair man!!

[@rolandosalgado1552]

Thanks for share, very important procedure for test the signals to turn on the backlight leds, !!!! :)

[@uyijohn6072]

thanks very much i just fix one with the jumper from lcd en to 3.3v

[@electronicsrepairschool]

thats great, make me fell like ppl actually are learning from this channel :)

[@wificor27]

Hello, can you help me please¿? I have a Dell XPS 15 Laptop, the backlight is off before Windows, even in Bios. External monitor is ok with backlight. I Change the entire Screen (LCD+Cable) and still wrong. I see that with AC adapter the backlight brights 10% more than with battery only (10% darker almost invisible and image flicks a bit). The screen can´t dissasembly and i can´t manage the LCD board with inverter but Screen i purchased is new. I think can be a faulty motherboard but write to you for give to me some advice. Thanks very much. Regards.

[@kahlospirit24]

thanks for the video. what is that ribbon cable called? I have display by external monitor but not enough light. hoped laptop would be of inverter type but it isn't. it's a Toshiba c55 a 1n1 TruBrite® HD TFT High Brightness display with 16 : 9 aspect ratio and LED backlighting. so is it this cable I need to change first? hoping to avoid a whole screen purchase many thanks

[@alirafique1757]

thanks alot ..for teaching us

[@dsd2918]

Are there any videos on the laptop screen flickering problem? I have a 17.3 inch MSI LED laptop with a flickering problem. The back light is Ok, I can see the windows screen properly, but I'm annoyed working on it when it flickers. Also checked the HDMI port of the laptop with another led monitor, HDMI works perfectly. Please any solution? 😢😢😢

[@dhariprasad08]

Hi, my laptop got hdmi socket short circuit when connected to led tv. Both tv and laptop motherboard gone. Now i have replaced laptop MB, display not working. When connected to external monitor its working. I have check display cable and it is fine. Suddenly display started working for 10 secs and gone. Now replaced display working fine. Please let me know my display worked for seconds. Their might be loose connection or something.please advice me.

[@AyadEKorial]

Thanks 😊

[@esotericray5750]

I have an LP17WP4 LCD screen from an old laptop. I just want to use it for illumination but don't know how to make the connections. Would it work on 5 volts or I must apply 12v?

[@benedicternest4521]

Thanks so much for this tutorial!!

[@TrueHafiz]

Lenovo X240 LCD no backlight. everything else works. Need to use flashlight to see on the screen. tried every trick. no luck. Do I need to replace the screen? Please advise. Thanks

[@ANACONDA_2000]

What to check if there is backlight but not picture?I havent seen such situation i think on your videos as i remember

[@flat-earther]

My ASUS laptop screen has image but no backlight. 18:40 With the computer powered on I measured from ground to LED_EN 3.3V, and from ground to PWM 0.6V. 11:48 and this fuse does not have continuity. I should replace the fuse right? Is there anything else you suggest?

[@flat-earther]

Does the cause of the blown fuse have to be found? And if so how can I find out what caused the fuse to blow? Maybe there is a failed component or short circuit somewhere that caused it to blow?

[@ismailrhorbti1644]

I want to learn the Electronic repair of laptop and phone.if you have ser any course os that please and thank you very much of your video.

[@technicalsupport1571]

Very Accurate, Thanks for this boss.

[@jollycastillo2230]

where to get 19 volts if the problem is in the 19 volts hoping on ur positive response thanks

[@sadiqtv307]

thanks sir good job

[@RightEyeOfRa]

Great tutorial man! Thank you very much! I need to vape to get this job done!

[@inspectormag]

PWM is Pulse Width Module :)

[@worshiperjbannan313]

Sir good evening pls where do find the fuse on dv 6-6143so mother board

[@stairway71]

Hello there. Can you tell me how much power does a laptop screen require to light up. I ve a damaged screen which gave only white light while attached to laptop. I want to use the laptop screen as a light for some other purpose. Can you help?? Sounds crazy doesnt it

[@computersrepaircotesaint-l7407]

Thanks very much again

[@charlesdoe800]

very good

[@easypipsforex4741]

Thank you for sharing your knowledge. great videos. gracias

[@khalidkhatri2602]

Hi you are great man 👍

[@SUIN1]

Thanks. whit this video i found a short to ground of pmw signal in the video flex.

[@geojor]

PWM is pulse width modulator, the faster the frequency the brighter the light, would you agree ? thank you ...

[@donfoumare]

No.. the brightness depends on the pulse width not the frequency. The pulse width is the time that a signal stays at logical high within a period of time before it falls back to logical low!

[@shj802]

how can i find pwm, b+, b_on, gnd if those are not written on the board?

[@faiyaz693ify]

Thank you sir.