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geekhack Community => Other Geeky Stuff => Topic started by: pex on Tue, 17 August 2010, 07:37:06

Title: Why do I have to torque my laptop LCD to get the picture?
Post by: pex on Tue, 17 August 2010, 07:37:06
I came onto a laptop on the cheap because somehow one of the USB sockets was busted (no idea how this happens, if you were to see it) and the  LCD has crazy distortion.

However, torquing the monitor (by holding onto the left side or top and bending the upper left corner toward the body) the picture can be improved, doing it just right causing the proper picture.  Untorquing the LCD sends the image back to distortion.

My first and only guess is that a solder came up somewhere or something conductive is bridging components, and the torquing bridges or unbridges as needed.  What is the likelihood that I will be able to tell with the naked eye what the issue is?  

I took most of the laptop apart but haven't gotten to LCD disassembly yet.  I guess I meant to contact one or more manufacturers on this, or maybe I did and they never responded.  I don't really recall.
Title: Why do I have to torque my laptop LCD to get the picture?
Post by: pex on Wed, 18 August 2010, 01:24:27
Here is a nice thread from someone with a similar issue.  I will work from that and report back.

http://www.diybanter.com/uk-diy/258021-laptop-lcd-screen-problems.html
Title: Why do I have to torque my laptop LCD to get the picture?
Post by: ThirdLap on Wed, 18 August 2010, 04:00:48
Quote from: pex;213416
I came onto a laptop


This may have something to do with it.

Quote
However, torquing the monitor (by holding onto the left side or top and bending the upper left corner toward the body) the picture can be improved, doing it just right causing the proper picture.  Untorquing the LCD sends the image back to distortion.


It sounds like your laptop likes it rough.

Quote
What is the likelihood that I will be able to tell with the naked eye what the issue is?  


Very unlikely.  I would get it naked first.
Title: Why do I have to torque my laptop LCD to get the picture?
Post by: ch_123 on Wed, 18 August 2010, 08:15:02
Quote from: pex;213416
I came onto a laptop on the cheap because somehow one of the USB sockets was busted (no idea how this happens, if you were to see it) and the  LCD has crazy distortion.

However, torquing the monitor (by holding onto the left side or top and bending the upper left corner toward the body) the picture can be improved, doing it just right causing the proper picture.  Untorquing the LCD sends the image back to distortion.

My first and only guess is that a solder came up somewhere or something conductive is bridging components, and the torquing bridges or unbridges as needed.  What is the likelihood that I will be able to tell with the naked eye what the issue is?  

I took most of the laptop apart but haven't gotten to LCD disassembly yet.  I guess I meant to contact one or more manufacturers on this, or maybe I did and they never responded.  I don't really recall.


I have a very similar issue with my Thinkpad. Sometimes if I angle the screen back, I get horizontal white lines and in some extreme cases, the screen starts to white out. Moving the screen forward, or grabbing the screen bezel and exerting pressure on it, or even just tapping the back of the screen causes it to go away.

Reading into the problem, it appears that it's caused by the cable going from the laptop to the LCD becoming either loose or damaged. However, given the amount of effort that it would involve to get to both ends of the cable (basically fully dismantling the whole laptop) relative to the severity of the problem, I haven't bothered.
Title: Why do I have to torque my laptop LCD to get the picture?
Post by: pex on Thu, 19 August 2010, 22:03:10
I poked at my cords and boards attached to the LCD, and whatever board is at the top seems to affect the display.  Then I sent an e-mail to totally random LG e-mail addresses because I can't find a contact info on the lgdisplay.com website.  All addresses were found via google.

Quote
Subject: LP171WX2(A4)(K9) lcd issue‏
To: irATSIGNlgdisplayDOTcom, worldno1ATSIGNlgdisplayDOTcom, beachanATSIGNlgdisplayDOTcom, islee72ATSIGNlgdisplayDOTcom
Sent:   Thu 8/19/10 10:09 PM

I have an LG.Philips LP171WX2(A4)(K9) lcd display issue.  The LCD will display /something/, but not what it is supposed to, mainly bands/lines of colors. If the screen is bent slightly from the left or top side so the top left corner is twisted  toward the user, the display will still have bands but will partially display the appropriate image.  If it is twisted to a certain precise position, the image will be completely appropriate without issue.

I removed the LCD from the laptop which encased it and manipulated the wires to the LCD and inverter without effect to the display.  Poking at the A4 PCB, P/N: 6870S-0153D, ASS'Y P/N 6A222K L737D1,however, did affect the display, but this did not help me understand what portion of the board included the issue.

Are there certain common points of failure I should pay special attention to in trying to diagnose and alleviate this issue?


I don't know what that top board is called.
Title: Why do I have to torque my laptop LCD to get the picture?
Post by: Rajagra on Thu, 19 August 2010, 23:14:14
There are usually several connectors inside LCD displays. Some are zero insertion force, some are push fit, and some are just squeezed between components during manufacture. Problems like you describe are often caused by the connections you can't fix (the 3rd type.) You can try reseating all the removable connections, but if that doesn't work an expensive part - the LCD itself - probably needs replacing, which can cost more than a new laptop.
Title: Why do I have to torque my laptop LCD to get the picture?
Post by: Dean on Wed, 05 January 2011, 00:48:40
He has fixed it, check his project log, he had to resolder the plug.