noisy display

[Purpleyeball]

A few minutes after starting up my laptop (T42), my entire screen starts to get noisy. The noise appears as horizontal line static, getting slightly worse on the right side of the screen. The static gets worse, then better, then worse with no apparent pattern. At first, I thought it was associated with being plugged in to AC power because I could run it on the battery and the problem would not occur, but that is no longer the case.

An important thing to note is that I just had the system board replaced (by Lenovo) just 3 weeks prior to this problem first appearing.

Any thoughts or suggestions about this problem are appreciated-

[christopher_wolf]

Welcome to the Thinkpad Forum

Sounds to me like a hardware problem as it is getting progressively worse; just to be sure, have you updated to the latest video drivers?

[laz]

I'll bet it's a loose connection. You could go in yourself and try tightening things up, or just send it back and make them fix it.

[cmarti]

Purpleyeball,

The same thing happened to my T4o last year, the problem was a loose connection on the inverter.

Give it a try and check all the connectors in the lcd area before it get worse.

[Purpleyeball]

Thanks for the comments! It wasn't the video drivers. A loose connection somewhere sounds likely. I wasn't able to find it myself very easily so I sent it in for fear of messing something up by poking around inside it. Whatever it is must be related to the recent installation of the new system board, so hopefully they will fix it at no charge...

[roberts5]

Mine was doing the SAME thing today. Horizontal noise, worse on the right side. Took it apart and reconnected the video cable at the lcd and the board. Its seems good, but the video cable to mother board connection must be TIGHT.


EDIT: Its not the connection. Now I can't get it to go away no matter what I do w/ the connector. I plugged in my old XGA lcd and cable (upgraded to SXGA+) and this seems fine. Going to try changing the cable. Hope its not the LCD.

UPDATE. I'm pretty sure its the LCD. A new SXGA cable didn't help. So its either the LCD (I think it is, it was bought used and showed ware, I had to replace the cathode tube), or the video card can't drive it anymore, but I doubt its that.

Also, heres some pics, for future reference.

[Purpleyeball]

Thanks so much for your comments and pictures, they are very much appreciated. The pictures posted look exactly like the problem I am having. After sending it in to Lenovo, they said it was the LCD screen gone bad. After not being able to get anybody there to explain what they did, I asked them to return it without repair, as I am very hesitant to invest that much more into this computer. I have been pretty dependent on it for the last couple of weeks and have still been using it. For the most part it works fine on battery power, but when I plug it in, I get the noisy display after about a minute. The problem is not getting any worse.

My screen is an SXGA+. I took the computer apart myself to check the LCD connections (inverter connection and connection to the board), and reconnected everything, but none of this seemed to fix it.

The symptoms suggest that there is a problem with transmission of information from the video card to the LCD, and I've been hoping that it is not due to the LCD itself, but so far, it doesn't sound promising.

One last thing to note is that my display looks fine on an external monitor.

[roberts5]

Well I just bought a new LCD from this guy:

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0078396695

Made an offer of $190, he came back at $204 and it was only $25 shipped over night.

I will let you know how this works out for me. Also, replacing the LCD by yourself really isn't too bad. A mild pain in the [censored], but once you know what your doing its a 30 min job.

[Purpleyeball]

Thanks for the excellent tip! That's easily the cheapest price I've seen for the LCD. Please let me know how it works, and I think I will follow your path.

[mitchellst]

I recommend plugging it into an external monitor. If the problem shows up on the external monitor, then you need to hit lenovo up for another motherboard. If the problem isn't on the monitor, then it is probably your LCD.

Another simple test, is applying pressure around the palmrest and keyboard area. Also try this around the lcd (not much pressure). Just test to see if moving either gives the noise. A lot of times, if it's your motherboard, applying pressure to the palmrest area will trigger the defect. Don't want you to crack it though.

Considering that you just had your board replaced, you should really test this. Lenovo's techs probably aren't paying attention to your prior repairs unless you left a note taped to your LCD or some other obvious display. A lot of things get overlooked. Often times, diagnostics get rushed.

[roberts5]

Well...this sucks. New screen came in. First off, theres a sticker on both the packaging and the back of the lcd that says "QC FAILED". That was disheartening. Plugged it in, problem still exists.

So that means one of two things...the new screen is also bad (I doubt it), or its a motherboard problem. I read this thread: http://forum.thinkpads.com/viewtopic.php?t=32881 where a guy with the same problem said:

Just an update to this, I found a workaround: by underclocking the video chip's core frequency this distortion goes away completely. I underclocked from 250mhz to 100mhz... haven't tried other speeds yet.
I guess I need a new motherboard.

So the problem doesn't exist for me on an XGA screen. Doesn't exist on an external monitor at 1280x1024, but does exist on the SXGA LCD.

As I've stated before, I've tried replacing both the cable and the LCD. Not together, but separately. So this leads me to believe its the video chip.

The problem with this is that I have a warranty, but the computer came with an XGA screen, and I can't replicate the problem that screen OR an external screen. So I'm not sure where to go from here.

I'll keep you posted.


MORE UPDATES:

Its definately the video chip. This really pisses me off, this is the third chip to fry on me. The Radeon 7200 is a piece of $hit. Heres what I've done (which I'm an [censored] for not doing before buying new parts). I connected an external monitor w/ the SXGA LCD in. I was shocked to find out that not only does the external monitor look fine, but the LCD looks fine as well!!! As long as the external monitor is plugged in and actived (not even primary) the LCD seems fine.

I've also been playing with ATITool (found here: http://www.playtool.com/pages/undercloc ... wdown.html) and found that changing the video speed has a large effect on this problem, from making it much worse to almost gone. Whats weird is that its not only slower that helps, going higher seems to help as well.

Anyway, enough of my ramblings, end of story, it seems that this is a video chip problem.

[roberts5]

Sent it back to IBM. They replaced my Motherboard. So far, so good.

[mitchellst]

I knew it.

[Purpleyeball]

Thanks for the updates.
It makes sense that the problem is with the motherboard, since this problem started on my computer within 3 weeks of having my motherboard replaced by IBM. Grrrrr.

[Purpleyeball]

I sent my computer in to IBM, and they finally replaced the motherboard. It turns out that when they replaced it before, they put the wrong one in due to a mislabeled part. I am guessing it did not have the appropriate video chip for the high resolution screen, which would explain why it worked when attached to a lower res. screen.
Anyway, it works great now that it's got the correct motherboard in it. yay!