TechSpot

ATI Radeon Mobile 9000 on Thinkpad T41

By francescoo
Jun 30, 2008
  1. Hi,
    this is the first time I post here and it regards a problem I have with a second-hand laptop (IBM thinkpad t41) that I just bought.

    The laptop has got an ATI Radeon Mobile 9000 and the problem I have is that the display on the laptop very frequently starts blinking and getting fuzzy, with apparently no reason.
    The problem is especially bad when I try to send the signal to an external tv and to the display at the same time (the display gets really fuzzy and blinking, but not the tv).

    I have tried to uninstall and install the drivers many times, I tried with different types of drivers (with the omega ones by the way I could not show the screen on the laptop display and on an external tv at the same time) and I tried to change several options... no result.

    I do not have any problem if I unistall all the video card drivers and if I watch the screen just on an external tv. In particular, the screen on the external tv is always fine, I do not get any kind of problems here.

    Any idea on how to solve this problem? I still have some weeks to give the laptop back if I want but I would rather prefer to fix it if possible.

    Many thanks
    Regards
     
  2. CCT

    CCT TS Evangelist Posts: 2,653   +6

    Since it occurs ONLY on the LCD and not the output port, it appears you have a bad cable, bad cable connection, or a failing inverter.
     
  3. francescoo

    francescoo TS Rookie Topic Starter

    Thanks for the answer!

    So if the problem is one of these then it should be quick and cheap to fix. But how can I test if it is the display itself that is defect?

    Thanks
     
  4. CCT

    CCT TS Evangelist Posts: 2,653   +6

  5. francescoo

    francescoo TS Rookie Topic Starter

    thanks, I now have to decide how to proceed.

    If it is an inverter problem I will be happy to replace it, considering that the laptop was a very good deal. If it is either a display or video card issue then I would return the laptop.
    If I start now opening and changing parts I will then have some problems to return the laptop, on top of possibly wasting the parts I will install.

    So, is there a way I can use to have an even rough idea if the defect part is:
    - video cable
    - inverter
    - display
    - video card?

    When the display gets fuzzy, on top of blinking and getting partly or totally black for very short periods, I also get what I can describe as pixels moving fast right and left, especially on the borders of open windows. This disturb seems to happen either randomly or when I have a lot of stff running.
    Two things ALWAYS cause this disturb:
    - trying to view the screen both on the laptop and on an external tv
    - running some kind of video card diagnostics (for example pc-doctor).
    But I repeat, the disturb is ONLY on the laptop display, not on the external lcd.
    I hope this info can help

    Many thanks again for the precious help
    Regards
     
  6. francescoo

    francescoo TS Rookie Topic Starter

    hi, after once more reinstalling the drivers for the card and the display i do not get anymore blinkings. I still get the disturb on the display from time to time, especially when i switch between the display and the external tv.
    Attached an example of the disturb, in a moment when it was particularly bad (i was running a video card test).
    What do you think? Inverter, display or card problem?
    Many thanks
     

    Attached Files:

  7. CCT

    CCT TS Evangelist Posts: 2,653   +6

    I have No idea!
     
  8. raybay

    raybay TS Evangelist Posts: 7,241   +9

    Go to the www.lenovo.com site, Enter your Type number from the bottom of the thinkpad, then run all the drivers from there if you have not dones so, beginning with the System Update 3.14. It would be a good idea to delete the old video graphics drivers in your Device Manager once you have a fresh driver available.
    Use the Driver Matrix to assure that you have all the latest drivers, if you have not already done so.
     
  9. raybay

    raybay TS Evangelist Posts: 7,241   +9

    A failing inverter will also cause this.. a new inverter is $15 to $30 on eBay, but you will have about 18 screws to remove and replace. Be sure you have the rubberized screw covers before you begin.
     
  10. francescoo

    francescoo TS Rookie Topic Starter

    Hi,

    I have replaced the inverter but the problem is still the same.
    Any other ideas or should I just return the laptop?

    Many thanks again
     
  11. CCT

    CCT TS Evangelist Posts: 2,653   +6

    If this comp is under warranty you shouldn't have opened it at all. If you can return/exchange it, I'd do so!


    If you cannot, however, then the graphics card should be checked to be seated properly (re-seat it) and the graphics cable should be checked to be seated properly BOTH ends (re-seat it).

    This involves a LOT of disassembly (and risk). You need to balance the odd glitch against that risk.
     
  12. nickc

    nickc TechSpot Paladin Posts: 923   +11

    CCT, did u read the thread this is an onboard video in a laptop.
     
  13. Rick

    Rick TechSpot Staff Posts: 4,573   +65

    This isn't an inverter issue.

    The "inverter" supplies power to the backlight of the LCD screen. More specifically, it takes a low voltage and turns into a really high voltage that is able to light up the fluorescent backlight(s). I've replaced hundreds of them and have never seen an inverter distort the screen image.

    In fact, if your inverter didn't work AT ALL, you can still see the image just fine on your LCD. It's just really, really dark. It has nothing to do with any distorted images displayed on your screen.

    What you have in the image is a problem with your LCD's ability to display data accurately. This is most likely the fault of your graphics chip or data cable. The cable would be a cheap fix, but a new graphics chip is an impossibility - it *is* the system board, really.
     
  14. francescoo

    francescoo TS Rookie Topic Starter

    Hi Rick,
    thanks for tip.

    Is there a quick way to understand if it is the cable or the card itself?
     
  15. raybay

    raybay TS Evangelist Posts: 7,241   +9

    Look at your Device Manager (Start->Settings->Control Panel->System->Hardware->Device Manager) to see if there are any red or yellow flags.

    The inverter does not supply power to the screen in a Thinkpad. Rather it's job is to Invert the signal from a negative image to a positive image, and cleans up related problems. Since it is an integral part of the signal filtering and inverting, it can introduce a number of issues as it begins to fail. The power comes from the board. When the inverter begins to burn out, you will get similar symptoms to what you describe... But since you have replaced it, that is likely not the problem unless the replacement was defective. I also assume you looked for any sharp creases in the cable.

    The red or yellow flags in Device Manager can be an indicator that the driver is bad, or that the flat video graphics cable is not properly seated. But since you would have reseated that cable as part of the inverter re-install, that is not it, either. I assume you have replaced the driver, and installed the new driver AFTER removing or disabling the old driver.

    Some (a very few) of the T-4x series Thinkpads had defective systemboards for which the video graphics failed early... on only a few certain type numbers. On these, you usually must replace the system board. But sometimes it is the LCD screen rather than the system board, so it is good to have another machine with which you can trade out parts.


    You might also want to go post your problem on the Thinkpad Mailing List,
    http://stderr.org/cgi-bin/mailman/listinfo/thinkpad
    and on Bill Morrow's thinkpad site, www.thinkpads.com
    because a lot of the members of that list have had experience with the rare T40, T41, T42, and T43 video graphics problems. Both sites have users who are true experts on any stage of any Thinkpads.
     
  16. CCT

    CCT TS Evangelist Posts: 2,653   +6

    Well, yes I did - and I obviously missed that the Mobile Radeon isn't quite so mobile.

    So shoot me!
     
  17. nickc

    nickc TechSpot Paladin Posts: 923   +11

    I didn't mean it that way.
     
  18. mjkt41

    mjkt41 TS Rookie

    Have you tried unplugging the AC adaptor?

    Hi, I have a T41 with the Ati Radeon 9000 chip that experiences the same fuzzy screen as in your picture. It is particularly bad with apps like Google Earth and seems to be triggered by cursor movement. In my case, I can get the symptoms to go away just by unplugging the AC adapter. Have tried 3 different adapters and done it in multiple locations. My problem is intermittent. I have the latest drivers, have tried all of the various Ati settings for acceleration, etc.

    Could my problem be caused some interaction between the graphics chip and the battery charging circuit? Thoughts appreciated.

    MJK
     
  19. CCT

    CCT TS Evangelist Posts: 2,653   +6

  20. francescoo

    francescoo TS Rookie Topic Starter

    Yes, I also noticed that unplugging the laptop the problem goes away. That is because the powerplay reduces the performances of the video card when the laptop is unplugged.
    So I checked if it was possible to have the powerplay activated all the time, even with the plug in, but I could not find a way. So I installed the ati tray tools and I underclocked the card. To be precise I decreased the GPU speed from 252 to 131. I did not modify the memory value (200). I know that in this way I reduced quite a lot the performances of the video card, but at least I got rid of all visualization problems. Also, I modified the drivers as described here, to avoid system errors http://www.techspot.com/vb/topic15393.html.

    I just wonder if this could be a long-term solution or if the video card will just get worse and I will have to underclock again, and again, and again...

    Also, I cannot understand why, even without undercloking and with the plug in, I have never had any problems on an external monitor (is it less performance-intensive to use an external monitor than the display? I do not think so...)

    Hope this can help!
    Bye
     
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