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  How to troubleshoot laptops? 
 
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david sopala Mar 22, 2006, 06:36pm EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
I would think it might be the cable, screen, or you just can't see the image. Try the flashlight trick. Here is the basics from what I have seen while having my LCD apart.

Inverter is just a DC to AC converter that steps the volatage up to drive the CCFL.
The CCFL is just a light (think lightbulb) it either comes on or doesn't.
The cable brings the data into the LCD.

That having been said now the question. Which is it? Well since you get a clean image on a regular monitor the graphics card is alright(unless it is a problem on the LCD cable bus). Momentary white flash - CCFL should be ok since it seems to turn on at least for a second. Inverter - maybe or maybe not I say this only because I assume you tried quite a a few times rebooting etc and it flashed every time (assuming the brightness is up it is unlikely). The screen itself - still a possibility I haven't ever seen a screen go bad in person so I don't know how it would act. Or the cable - if you open the screen you can visually check it and see if it looks messed up or not. My money would be between the cable and the LCD itself since there is no image.

conc - LCD screen or cable.

Thats just my take on the situation - I have no formal training in laptops just what I have learned from the internet and hands on experience.

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Tom Colson Jun 01, 2006, 06:48pm EDT Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
I have a Dell Inspiron 8600 with a dead screen: 15.4" WSXVGA+, Hitachi Part # TX39D97VC1FAA. Here's what I've done:

External Monitor: Fine.
Wiggled and reseated the flex cable: Nothing
Reseated the Inverter cable: Nothing.
Flashlight on the screen: Can't see desktop Icons
FN Brightness: The display get less or more black, and the backlight gets less or more bright.
No Battery and PS: Nothing.

I don't think this unit has a replaceable backlight, so how do I trouble shoot this?

There is no damage to the screen itself.



Patrick V. Jun 01, 2006, 07:54pm EDT Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
hi guys, I knw this is out of the topic but one question.... I bought a laptop and Its a Celeron and on 256mb ram i knw its slow but i just want it to make it a bit faster in opening applications.. Is it advisable to change the rab to 1gb? will it make a big difference?

thank you

2.4GHz Core 2 Duo
GIGABYTE GA-965P-DS3P
2 GB Corsair Twinx DDR2 800-PC6400
Western Digital Raptor 74GB
Seagate 400GB HDD
Asus GeForce 8800 GT
22inch CMV Chimei
Shadow_Ops_Airman1 Jun 01, 2006, 08:11pm EDT Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
tom all i can say is find another laptop monitor.

AMD Athlon XP-M 2500+ (133x14= 1867MHz) (209x11= 2299MHz)
DFI LP NF2 Ultra-B (Hellfire 3EG Rev2)
Antec SX800, Neo HE 500, 4 Antec 8CM Fans
Thermalright SI-97 1 Antec Tricool 12CM Fan
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2x Samsung Write
Diogo Maciel Oct 25, 2009, 03:40pm EDT Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
Hey guys!

My HP DV9540 has a problem with screen like some of you guys. The difference is that when I turn it on, white lines come up and thats all I see while its on. White likes, sometimes white spots and thats all. I hear windows starting and stuff, and I dunno how to switch to TV without going to control panel to check if everything is ok... You guys have an idea what part should it be?

Thanks a lot!

Laptop Willie Oct 27, 2009, 09:07am EDT Reply - Quote - Report Abuse
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Edited: Oct 27, 2009, 09:07am EDT

 
>> Re: How to troubleshoot laptops?
Diogo Maciel said:
Hey guys!

My HP DV9540 has a problem with screen like some of you guys. The difference is that when I turn it on, white lines come up and thats all I see while its on. White likes, sometimes white spots and thats all. I hear windows starting and stuff, and I dunno how to switch to TV without going to control panel to check if everything is ok... You guys have an idea what part should it be?

Thanks a lot!

There are two things it could be. 1) The LCD cable could be bad, 2) The LCD is bad. Most likely the LCD has broken connections on it and is most often unrepairable. It should be replaced.

Laptop Willie
check out laptopwillie.com
john albrich Oct 27, 2009, 09:15am EDT Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
Diogo Maciel said:
....I dunno how to switch to TV without going to control panel to check if everything is ok...

A number of laptops have a special Function key or key combination that lets you easily switch between LCD/TV or both. Your owner manual should show you how to do that.

John Wheatcroft Nov 04, 2009, 03:11am EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
I have a similar problem on an IBM / Lenovo Thinkpad R61i

I have fitted a new screen which we know works as we have a faint image. We also have a new backlight, which we also know works as we have tested it.

We purchased a new inverter from our supplier which we also know is new as we have tested it and it does indeed produce the required voltage fro the CCFL backlight.

Thing is having fitted these items we STILL have a dark wcreen but we DO have a faint image. I am guessing there is some sort of protection device on the main board, like a fusible link which nneds replacing.

Windows boots, dark screen, new inverter, new backlight, new screen - anyone had this problem or knows where the priotection device on the mainboard is. Thinkpad R61i

Suspended User Nov 04, 2009, 10:31am EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
John Wheatcroft said:
I have a similar problem on an IBM / Lenovo Thinkpad R61i

I have fitted a new screen which we know works as we have a faint image. We also have a new backlight, which we also know works as we have tested it.

We purchased a new inverter from our supplier which we also know is new as we have tested it and it does indeed produce the required voltage fro the CCFL backlight.

Thing is having fitted these items we STILL have a dark wcreen but we DO have a faint image. I am guessing there is some sort of protection device on the main board, like a fusible link which nneds replacing.

Windows boots, dark screen, new inverter, new backlight, new screen - anyone had this problem or knows where the priotection device on the mainboard is. Thinkpad R61i


The bets way to diagnose that issue is to connect an external monitor. I would say the LCD is DOA and you need another one.

Laptop Willie Nov 04, 2009, 10:58am EST Reply - Quote - Report Abuse
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Edited: Nov 04, 2009, 10:59am EST

 
>> Re: How to troubleshoot laptops?
John Wheatcroft said:
.............Windows boots, dark screen, new inverter, new backlight, new screen - anyone had this problem or knows where the priotection device on the mainboard is. Thinkpad R61i


If you have a new screen, why did you get a new back-light? The back-light should be built into the LCD. The inverter is plugged into this. If you plug the back-light into the inverter and power on, the light should light up, whether installed or not. Please there is a way to switch between the LCD and an external monitor. This is a three step switch that turns on the LCD or the external monitor or both. If the cable going to the LCD has the inverter cable built into it, you may have a cable problem. There may just be a loose cable connection to the video board/motherboard. Good luck,:)

Laptop Willie
check out laptopwillie.com
John Wheatcroft Nov 04, 2009, 12:33pm EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
You have misunderstood the question I asked.

I did not say that I got a good picture on a regular monitor at all.

I said that that having fitted a NEW WORKING LCD panel and a NEW WORKING INVETER
and we know the CCFL is OK as we have checked it on another machine.

We cannot get the backlight to come opn on this particular machine, therefore it must be a protection on the mainboard of the laptop itself. Do you know where these are situated

Thanks

Freddy COMPUTER Jul 01, 2011, 09:14am EDT Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?, Regards LCD Going Black...
Well, here is my experience, My Laptop after turned on for a good 15min. regardless what i was doing would dim. and would not undim unless i would restart it. well i started troubleshooting and i placed new heat compound on processor and on the video card witch use the same heat sink.. i cleaned out the fan using compressed air bottle . put it back together and it did it again.. but atleast i new it wasnt temperture problems.. i reviewed all settings on power and on screen settings and all was default.. so i decided to check LCD. I went and got a external screen and plugged it in, everything look as on my laptop, I waited 15 minutes and it happened! The laptop went black but the external didnt.. only three things left.. LCD, LIGHT BULB, or INVERTER... lcd workes fine because no dead pixels nor color change.. next light bulb works but not forever. but works.. so last is ofcourse the inverter.. so rather take a chance and buy a new lcd and bieng the inverter i bought the inverter, and WALLA God is Good... till this day... i didnt regret starting at the processor nor the video card cleanning fan nor placing heat compound because i tend to use my computer on rug and bed and it sucks up dirt and it could of been a temperture problem if processor and video gets hot it will shut computer and give video problems... but lucky me it wasnt.... good ooo inverter.. hope this helps... be wise


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