Laptop display trouble shooting, LCD or motherboard?

I just picked up a Thinkpad T400 to fix for my use.

Has intergrated graphics ( ATI ) . Making it cost effective once its all fixed up is my goal and hope, its a nice model Thinkpad.

The laptop works fine on a external monitor, however the internal display has problems.

It appears to be fine for a few sec, with a thin green line at the top of the screen, then horizontal lines and odd colors , then works fine for a few seconds . Even in bios you can manage to get around, however the screen jumps around, like an old analog CRT with bad sync settings.

I just would like a confirmation the LCD display is bad, before thinking about replacing it or trying to find a used one. ( if its the motherboard then I will just use it as a parts machine) .

Hope this is enought info to answer my question, please add comments if more info is needed.

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Deck the Halls
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Brian, since it is working fine with an external monitor, I seriously doubt it is the motherboard. I would probably start with a new inverter, then an LCD. Also, check the cable, it is possible that it does have a short in it, which could cause that behaviour. Something like this should work and it's not to expensive. Hope this helps, good luck.

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thankyou oldturkey03, As of now it seems your right, after leaving the laptop alone for a bit the display seems to be working normally (loose connection). Which will be great, saving me the cost of an LCD would be a huge help.

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Brian, hope it works out. Let us know what develops. Good luck.

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yes, i will post updates, its giving me issues for sure. It also keeps wanting to boot from intel management BIOS extension, intel ME Firmware version, not sure what that is...... It also wont power off or restart correctly......... seems i have more work to do on this then i thought.

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well im pretty sure its not an inverter issue, no change in moving or taping display frame. I have to take it apart to test the display cable later today. I would imagine if the display cable has a bad connection, the issues should change? or be normal once i remove and reattach the LCD display cable connector on the motherboard ? See, i would think with normal movement or flex moving the computer, tapping on the frame where the display cable is, I would see a change? and i haven't......... I just want to diagnose this correctly before ordering anything since that will add time and cost to getting it fixed up and ready to replace my current computer. So if you have any further thoughts based on this additional info/comments oldturkey03 or anyone else, please share them. OH and the display doesn't work very well actually, after having it a while now the screen constantly jumps, every sec. or so. (hard to explain verbally but can provide more of a description if necessary).

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I do agree with you, and as you know, the hardest part is always the diagnostics. Check the cable where it goes through the hinge, make sure it is not broken or shortening out. Any chance you could check the voltage on the inverter.

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Try wiggling the screen; any difference?

If it works after a little while of being on, and the cable is not the issue, it's possible there is an issue with the ATi (AMD) chip, I've had it happen to an old laptop before. Although that should be easy to fix.

Apparently sometimes the external monitor runs off a separate chip, on some laptops.

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wiggling the screen or moving, taping on the frame make no difference. It does go away after awhile if i can get it to boot up correctly into my OS. If there is an easy fix for the issue you mentioned let me know ? ( ATI chip thing). Not sure if the laptop you had was a thinkpad, The model thinkpad i have, a T400 is fairly new and i am used to working on the older T60/61 series.

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I haven't seen many recent ThinkPads because they're built well and don't usually break and get thrown out, but the last one I saw was an old Pentium 4 one with a similar problem to yours, and it had an old ATi chip, perhaps a ATi 7500. At the time I was quite little and didn't know about surface mount rework, so I don't have experience on it, unfortunately.

The ATi chip issue is fixable with a heat gun, sometimes, as evidenced by the YouTube tutorials about Apple laptops and ATi chips.

I'd recommend a SMALL propane torch tho, instead of the heat gun.

You'd want to try to keep the temp of the chip around 217 degrees C for 30 seconds.

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Hello there I have a Leveno Y50-70 and the connector on the motherboard is broke. What is that part called on this I need to replace it and have no clue what part it is.. That's why it flickers so much for me.

Thank You in Advance :)

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Brian will be eternally grateful.
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