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  How to troubleshoot laptops? 
 
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Adam J Jan 19, 2005, 09:06pm EST Reply - Quote - Report Abuse
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Hey,

I have a chance of getting a Dell Inspiron 8100 pretty cheap because the LCD panel displays nothing. Running an external monitor works perfectly fine, so I know the video card is fine (even though this model tends to have problems with them). Someone told me it would be the backlight, invertor, or LCD Video Cable. How can I troubleshoot this unit further? I know I can pick up the LCD cable for pretty cheap but I don't want to keep buying parts here and there because then these "cheap" pieces add up to 100's of dollars and I'm stuck with a non-functioning laptop. It is a Dell, so it is bad as it is so I don't want to invest too much. Thanks

Also, when using FN + F8 to change between LCD and CRT the LCD will flicter red for a few times and that is all. Other than that the machine works just fine.


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Brian Stewart Jan 19, 2005, 09:12pm EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
Look close.
REAL close.

Shine a lot of light on it, and maybe no light at all.
Does the LCD display show the desktop and stuff?
If you can, but you can barely see it, then it's the backlight.

If you can't see the desktop at all (move the mouse around, maybe open a word document or a webpage with a white background) then it's most likely the video cable.

As far as the invertor goes, if that went out, there's a good chance it took other things out too.

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Adam J Jan 19, 2005, 09:23pm EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
Thanks, man! I'll give that a shot! If anyone else has any other things to add, please do. I appreciate it.

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Arkady G Feb 03, 2005, 09:50pm EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
Hi guys,

I am having the same exact problem with my IBM laptop. The symptoms are like those you described Brian - the LCD apears to be dead.. but in reality it is just VERY dimmed. So yeah i was told that it is either the back light or an inverter (whats an inverter anyway?) ... . Where can i find carefull instructions on how to replace those parts myself? WiIl an inverter and/or backlight lamp from an older Compaq of the same size fit in my TP X20? IS it rather easy to insatall?

Thanks :)

Arkady.

Adam J Feb 03, 2005, 11:11pm EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
It's a waste of time, man. It's hard to get a backlight because it has to be the exact same one and I called Dell and they didn't know what the hell it was.........damn Middle East tech-support. If the invertor goes it usually takes the backlight with it. You can get the invertor for like 50-100$.

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Arkady G Feb 04, 2005, 12:45am EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
... Yeah since my last reply i did some research myself ... it would be MUCH easier .. and perobably a little cheaper.. to find a used or broken laptop of your exact model on eBay... (no hard drive, messed up board), as long as the LCD is fine ... . and jsut replace teh whole unit. How about that eh :)

Adam J Feb 04, 2005, 02:22pm EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
Ya, I looked into that and most people are selling the used LCD's for like 270$. What a damn ripoff. And some LCD's are Hitachi, IBM, Sony, etc. You're supposed to find an exact replacement. I'm better off buying a cheap 600$ laptop.

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Ken LaDere Feb 11, 2005, 05:27am EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
Backlights arent propietary for the most part. You purchase a bulb, Solder the origional leads to it, Install the isolater boots and its ready to install. Bulbs/CCFL's are cheap in comparison to a parts machine and if you need help yell.

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Adam J Feb 12, 2005, 03:51pm EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
Ya, that's what I was going to do but then I found out the owner of the of the laptop wanted like 400$ for it. It is a 1.1ghz P3, so what a ripoff when she'd spend like 300-700 do have someone else fix it. I expected to pay her like 200$ for it. I'll just buy a new laptop instead.

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Darryl Cooper Feb 20, 2005, 11:10am EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
Hi guys. I just want to get this out there and let people know that they are not scewed if they laptop LCD screen goes black, dim , red or pink. 99.9% of the time it is the CCFL back light bulb. On very rare occations it is the inverter. both items or inexpensive and are easy to change.You can find both on eBay or other sites.
the inverter goes for around. $50 and you can pickup a back light bulb for around $40.
there is a guy on eBay that sells back light bulbs for $35.00 all you need is the size of the bulb.
Here are some link that my help.

http://www.impactcomputers.com/
Ebay Item# 6744827336 Laptop LCD Back light bulb.

Good Luck

Please Delete Account Feb 24, 2005, 10:25pm EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
Hmmm...I've got one along the same lines, except maybe even a little more odd:

I've got an Inspiron 8200 with nvidia geforce go 440, and regular UXGA LCD (IBM). It was working when I shut it off, and then it was black when I turned it back on. Looking closely, I could see that the LCD was working, but the backlight was out.

So far so good...looks like a backlight/inverter problem, right? Well, when I looked more closely at the LCD, it was having SERIOUS problems displaying correctly, and in fact, it appeared the video card itself was malfunctioning. Windows would not boot into 1200x1600 mode without crashing, but I could get it to safe boot or boot into VGA only. In VGA mode, the LCD would work (still no backlight...it's completely off/dead), but it was clear that there were major video problems--the screen was flickering and being drawn with MANY errors.

When I booted the diagnostic CD and ran the video card diags, it consistently generated video memory errors.

So the question is: what's going on here? is it (1) the video card only? (2) the video card and some combination of the backlight and inverter? (3) Other?

As far as cause, was this a situation, where, as I read above, the inverter went and took other stuff with it? Yikes!

Thanks in advance....

Bob

Adam J Feb 24, 2005, 10:33pm EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
The Inspiron 8100/8200 have a lot of problems. If you hook an external monitor to it and that displays perfectly fine then it is the backlight or invertor (most likely backlight, the invertors rarely go). If the display on the external monitor is messed up then it is the videocard which is very easy to replace. It can also be the LCD video cable and you can get those cheap on ebay. Once you peel the screen away to the bulb you'll be able to tell if it is burnt out or not. That cable runs about 12$ on ebay.

Here are some links

http://www.jkllamps.com/

http://iantha.vectorstar.net/ccfl.html

http://www.bay-wolf.com/geforce4-1.htm

A backlight will be about 10-20$ but the repair takes a while and requires some soldering. The videocard is kind of expensive and would be the cheapest on ebay, maybe like 50-100$.


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Please Delete Account Feb 24, 2005, 11:22pm EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
Hmm...could a faulty video card (nvidia) keep the backlight from lighting up?

Darryl Cooper Feb 26, 2005, 01:42pm EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
It is possible that the video card would cause the back light not to light up but it depends on the system.
most of the time if you hook up an external monitor and it does not work then its the video card. If the back light
does not come on and the external monitor works it is either the CCFL (back light), the inverter, LCD cable
or I have even seen the suspend switch stick causing the back light not to come on.A bad back light most often will give you symptoms before they fail, like red or pink screen or very dim screen. Some model of laptops when the back light starts to go will put the inverter into a safety mode to protect the inverter from damage. I recently
repaired a Dell inspiron 3200 that had a red screen, I replaced the back light bulb it was even a 1/2 an inch short then the one that came out of the screen and still worked perfectly.

Good Luck everyone
P.S Do pay any attention to the manufactor when they tell you that you will need a whole LCD screen if it is
dim, red, pink or flickers.

Please Delete Account Feb 26, 2005, 09:49pm EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
Thanks...I'll check back in when I've worked it out. I think I'm going to pick up a new inverter and CCFL, along with a new video card. Honestly, I can't figure out which of them went wrong, and there are symptoms pointing to any or all of them (no backlight AND video card errors...but then the errors are intermittent, and when the video card is working error-free...STILL no backlight).

So, I say rip it all out and put new stuff in.

Thanks for the pointers.

Bob

Adam J Feb 26, 2005, 11:22pm EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
Hook it up to an external monitor and due a format and fresh install of windows and go from there. If it doesn't work on the external monitor it is the videocard.

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Please Delete Account Feb 28, 2005, 10:03am EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
Yeah, I'm just going to replace all of it; I found a great deal on a card, CCFL, and inverter. I'm also convinced by the diagnostics that there is a hard problem with the video card--whether or not you plug it into a regular monitor, it's still generating video ram errors and crashing at 1200x1600 (and flickering, distorting, and mis-drawing at VGA). I can't imagine that a bad CCFL or inverter would cause that.

The Inspiron 8200 seems to have had so many problems. I've heard about a lot of other people having trouble with it, and in fact, this would be the 3rd video card with this computer. I'm already on the 3rd motherboard, 2nd LCD, 2nd wi-fi card, 3rd ac adapter, and 2nd HD. Guess it was a lemon, but eBay can keep it alive for less than a new machine.

Bob

Terry Elliott Mar 01, 2005, 03:58am EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
I have a Toshiba Satellite 1800 laptop. The screen backlight kept blinking off and over several weeks got increasingly frustrating. A faint image could still be seen. I called a repair firm, they suspected a faulty inverter and quoted UKú150 for repair. On the verge of getting it ready to send away......I decided to have a peep inside the screen. I noticed some thin plastic tabs covering small screw heads around the edge of the screen. I peeled these off, using a thin knife blade. In fact, after removing them all, I needed only to have removed 2 to get at the inveter.

Remove battery and power supply!!!!!!!!!!!

These were one screw at each side of the screen, at the front, beside the hinges. Remove the 2 screws. Then, with a sharp blade, start to prise the plastic screen bezel off all round the screen. Gentle tugs will release the clips.

The inverter board is along the bottom edge of the screen, about 2 1/2" long and 3/4" deep. It is retained by one small screw. There are plug in connecters at each end. In my case, it was apparent that one of the plugs was slightly askew. I pushed it home firmly, crossed my fingers and switched the laptop on. Hey Presto, success!!

If I had actually needed to replace the board...it was easy to find them. I just put the make and part number into Google and they are available for around USD50. The whole job can be done in less than 10 minutes.

To replace the tube, you just need to remove ALl the screws and the screen will then seperate from the lid for access.

Please Delete Account Mar 05, 2005, 03:10pm EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
Ok, so I skipped the most involved part of my planned repair on my Inspiron 8200 (detailed above)--replacing the CCFL--and opted instead to drop a new video card and inverter in, and see what happens. Voila! So it was one of those two; I suspect the video card, but the inverter was cheap, so I'll consider it preventive maintenance at the very least. Still no definitive diagnosis, but I'm uncomfortable with ripping my machine apart, so I'll not mess with success for the time being.

Thanks to everyone for your help.

Bob

Please Delete Account Mar 05, 2005, 05:24pm EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
Note, after the fact: I swapped my old video card back in (it was much faster and had more memory), and everything still seems to be working fine. Apparently it was the inverter. Oddly enough, the bad inverter must have been causing the video card errors to come up in the diagnostics. Go figure.

Anyhow, the repair, even with the parts I didn't need, cost less than $60...much better than going to Dell for $700 for a new panel, or to the aftermarket, for $400 or so.

Bob

Darryl Cooper Mar 05, 2005, 06:28pm EST Reply - Quote - Report Abuse
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>> Re: How to troubleshoot laptops?
Hi I would like to know if you had removed to video card before you replaced everything.I'm just thinking
that maybe the card was not seated properly and by replacing it and reseating the card might
have fixed the problem. I just find it had to believe that the inverter would cause problems with the
video card, because all it usally does is steps up the voltage for the back light. But even though
thats the case electronics can do some pretty strange things even when some circuits are not
directly connected to each other.


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