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CCFL or Inverter Not working??

Posted: Thu Jun 24, 2010 12:02 am
by l8mkb
Hello Everyone,


I bought a T61p in jan-2008. I have sent this thinkpad to service centers for repair a couple of times, once for replacing the motherboard( the bios updater screwedup) and the other time for a broken LCD hinge. The service was excellent (they even sent me spare parts a couple of times like keyboard, touchpad etc).



A few months ago i spilled some beer on the keyboard, so immediately switched it off, opened the laptop and carefully cleaned everything. Switched it on, TADA it works as good as before.



A couple of months back i realized my warranty is about to expire so i though i would send the system for a final checkup. Now the guys at the service center tell me that there is a spill and to repair it i need accidental coverage which i don't have and cannot buy after the "accident". To repair it they asked for an advance of $800 - the laptop cost me around 1400,( new one on ebay around 400) it seemed to me that the cost of repair was too high. So they send me back my machine.







Now when i switch on my machine, i can see that the screen is active (if i look it at an angle i can see even different colors) but it is almost pitch black. I did some research, bought an inverter and lcd connection cords from lenovo and replaced the old one, no difference. Thought it must be the CCFL lamp, so bought a new lcd screen and replaced the existing one, still no difference. Frustrated, i removed the whole lcd from the hinge and connected my machine to an external monitor, this works perfectly.



My Question: Where is the problem, i replaced lcd, inverter, the connector cords. If there is problem with the graphics card the external monitor shouldn't work(i can even play games on it). Is there anything that can be done (a laptop is better than a converted desktop). Please share your expert thoughts, opinions and comments.



Thanks,

Elliot

Re: CCFL or Inverter Not working??

Posted: Thu Jun 24, 2010 5:00 am
by RealBlackStuff
Welcome to the forum.
Your problem IS the nVidia graphics card.
T61 models are notorious for this. It's caused by a badly engineered graphics chip, inside of which some layers become unstuck.
Unfortunately the only repair is to replace the motherboard.

BTW, the GPU has two output channels, a digital one to the LCD, and an analog one to the external monitor.
It's possible for one output to work, while the other does not...

Re: CCFL or Inverter Not working??

Posted: Fri Jun 25, 2010 4:35 am
by l8mkb
RealBlackStuff wrote:Welcome to the forum.
Your problem IS the nVidia graphics card.
T61 models are notorious for this. It's caused by a badly engineered graphics chip, inside of which some layers become unstuck.
Unfortunately the only repair is to replace the motherboard.

BTW, the GPU has two output channels, a digital one to the LCD, and an analog one to the external monitor.
It's possible for one output to work, while the other does not...
Thanks for the Input, i couldn't find an answer in Official Lenovo forums.

Re: CCFL or Inverter Not working??

Posted: Fri Jun 25, 2010 9:55 am
by sjthinkpader
There is a fuse on the MB for the LCD backlight. It is documented on this forum for T4x series but may be not for T6x.

Re: CCFL or Inverter Not working??

Posted: Fri Jun 25, 2010 5:24 pm
by wap32
Could be a fuse, has happened to me.

See this thread.