How to test whether lcd inverter or bulb is defective

[KWEKUONE]

my oh my... this is some great tip for everyone. an old toshiba satellite m45-s331 i'm working on has a major screen issue.  i just followed your tip, and the separate screen is on. i'm gonna order the backlight to see what happens.

thanks, pal. we appreciate people like ya.

[elgoose2003]

hey please is the green thing there the lcd inverter? mine only lights up wen i try to bearly connect it and wen i connect it all the way in it dont work it wont light the bulb that i know its working i just replace it, is that my main wires that connect the lcd what dont work or is it the lcd inverter? i have a thinkpad t60

[potugadu]

Hi Jarcomtech,

I have a Lenovo/IBM Thinkpad T60P laptop, its screen/display started going blank from last one week very frequently, I have to close the laptop lid and open it to get the display back up again. I am tired of closing & opening the lid every 5 mins so I am using an external monitor with the laptop.

Can you tell what could be the problem with my display?

I suspect it is the backlight because when I reduce the brightness to its lowest the display stay up longer.

Thanks.

[rapkabi]

Hi mate i followed you instruction and concluded that LCD inverter is broken cause there was no backlight. I ordered another inverter and is still not working :S

COULD it be mother board? or something else?

if its mother board what do i have to check? Please help mate!

[jarcomtech]

@rapkabi

Did you check if you have signal display when you when you connect an external monitor to it? If so then kindly also check your video/data connection going to the motherboard. You may need to "re-sit" for proper connection, then reconnect your new inverter and test again. Let me know how you progress...

[rapkabi]

@jarcomtech

I don't have external monitor so i connected to my tv with two male VGA connector and it didn't show anything :S

so what could be the problem?

thanks for reply mate!! m still repairing this same comp since 3 months lol

[Gatewayvick]

Pointless!!, like having your car not starting at all and like having an extra Starter for you car sitting around in the garage. Then putting it on your car to see if it will start or not? If it starts then you know the starter in your car is bad? The point is not many people have extra car parts just sitting around house and that goes for laptop lcd screens?

[jarcomtech]

Thanks for your comment. but pls be careful when testing the output of lcd inverter. If you use a tester you should set to an AC voltage of about 1K Volt. You can not power up the CCFL with just only 12Volts. Kindly check my blog at LaptopRepairGuide(dot)us on how to make a home made lcd inverter and bulb tester, or pls check my other YouTube video tutorial on the subjest matter. Good luck!!!

[adidhome1]

@jarcomtech what if my bulb backlight is good and the inverter is good as well what would be next reason why I don't get the backlight.

Not sure if it might have caused this but I have disconnected first the end from inverter that goes to the mother board and then a little bit of smoke came out of the computer.

The computer works well, except that I don't have LCD backlight, anything I can do to save this laptop?

[LogiForce86]

How about you just use a good old fashioned multimeter instead of a spare LCD? Since I doubt anyone has a spare LCD lying around.

You should get around 12V from the LCD end of the inverter. If you don't read anything or far less, then the inverter is broken. If you read 12V, it's the backlight.

[gimpsatchel]

@LogiForce86 wrong soooo many people know absolute shit. You are all talking out of your arses.

[LogiForce86]

@gimpsatchel Instead of just being a troll, explain how you do it so that people that are wrong in your opinion get it right.

And like I said, not everyone has a spare panel. So keep that in mind while you're at it.

[jarcomtech]

Hi, please check my new video entitled "How to test laptop inverter and bulb using a home-made tester". I hope this can help you solve your issue. Good luck

[slapmyfunkybass]

do you think for most people though it would be wiser to try another inverter and not another screen!

[jarcomtech]

Thanks for sharing a good tip to our visitors and subscribers. I used a crack screen because it is handy to me, as they are just lying around in my workplace, than getting another CCFL and wires to connect to it... but I appreciate your input. More power to you my friend!

[TehMG]

I use one of those $10 cold cathode light kits (the kit with a molex connector that you install inside a PC to "pimp it up". Comes with an inverter and 2 lamps.

To test the lamp in the LCD I just connect this external inverter to it, and power it with a computer PSU.

To test the inverter in the laptop/monitor, I hook up one or two of the lamps from the light kit to the laptop/monitor inverter output.

For just $10, it does a great job. No need to have spare LCD guts kicking around!

[Mustafalarf]

you know,, why did'nt i think of that, get another screen

and plug it in, amazing, or i thourght of another way,

you could get another inverter and plug that in!

this guy is a genius. thank you for your help, i now

do not have to think for myself.

[fatalcrixer]

what if i have a multimeter

[sorizaga]

what is the output voltage from a working inverter board should be? it should be ac voltage in what range? thanks

[ProfStuartHalliday]

@sorizaga - It's like 400Hz (squarewave) at 200V so most multimeters can't measure this.

[DiogNewmen]

I think you have to get the whole LCD Display-Screen. It's very complicated to try to remove the Tiny florescent tube. It's around $115 for a NEW LCD Display for a Laptop, so I'd take that over trying like mad with a $15 tube. ;^)

[twitsai11]

Thanks dude!

[42n8]

Thanks jarcomtech...

It's really useful to know that I shouldn't bother to test the inverter input to make sure it's powered. Your implication is that if it isn't the lamp then it's the inverter...

Let's see...

Connectors and componets fail, cables break and sometimes customers claim complete innocence when it's obvious that the machine has been reassembled incorrectly.

So we'll just test the inverter power input first shall we, it could save a great deal of time in the long run.

[DiogNewmen]

OR, you can just be abit Smarter, and actually see if the Backlight actually Comes-on for a few Seconds.

If it does WITHOUT Blinking or Flashing, then the Lamps are Good!

And the Inverter Board is Bad.

If the Backlight appears to be Unstable, Flickering like a Florescent Light that's bad, then it's the Lamp!

[MrKilltastic]

@DiogNewmen thats whats going on with mine, so i have a few questions:

is the lamp for an HP Pavilion tx 2000 models easy to find

is it cheap?

can i install it my self?

[manicmechanic22]

"You need to have another LCD screen" !

You'd make a great doctor - "we'll replace your head to see if it stops hurting, if does then thats the problem"

You buy the parts, then diagnose the problem - Well Done!

[bvandijk]

1 Kilowatt should be 1 KiloVolt... Even though my laptop gets pretty warm, I'm sure it does not burn over 1 Kilowatt...

[ruslroots08]

my sony laptop LCD is flickering what would be the reason why it is doing so? is it the inverter? or i just have to change my LCD screen? please help

[jarcomtech]

Getting another LCD as a tester is a faster and easier way for me to test the inverter, otherwise you need to buy a tester that has capability to test over 1Kilowatt of power, which I guess is more expensive. This I guess if very helpful and great tip for beginners... thank you!

[mmkirby2]

@jarcomtech Shouldn't the bulb be defective if there's a reddish/pinkish screen? My laptop can display a bright light for a fraction of a second then shut off itself but it doesn't display a reddish/pinkish screen.

[panrakesh1]

For a person like me this is really useful. I do not know if there is any other way to check except multimeter. Thanks Jarcomtech!!!

[mtjones12086]

Duhhh... wow what a waste of time. That is just common sense!

[SwanseaLaptops]

crap

[choppersteve22]

who has an extra lcd this is just pointless

[davids456]

@choppersteve22 YOU COULD BUY A CRACKED LCD OFF EBAY FOR ABOUT £5 YOU RETARD. OR YOU COULD PAY ABOUT £80 FOR AN INVERTER TESTER. YOU DECIDE.

[KWEKUONE]

@choppersteve22

no, it's not pointless. the problem lcd is with my toshiba satellite m45-s331 notebook.

i took an additional/extra lcd from a dell latitude d610. it worked.

his idea is great. try it; good luck.