Problem with garbled screen

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Revision as of 13:54, 13 December 2006 by Daniel.philipp (Talk | contribs) (Solutions)

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Information about the problem of a randomly garbled screen.

Problem description

The symptom is a totally garbled screen (on the internal display) as seen in these pictures.

This happens directly after starting up: even the BIOS splash screen is unreadable. The screen can stay garbled for a number of boots and then (seemingly random) it will be just fine right from the start.

It has furthermore been reported that there might be a relation between the temperature of the ThinkPad and the garbled screen, so that the display starts working fine when the ThinkPad has reached a certain temperature (like after 5 minutes of being powered on). Also by applying pressure to a certain point underneath the ThinkPad (on A30s its below the information sticker on the underside). This seems to affect the garbled screen even more, which is highly noticable on a LILO boot screen like so.

If the screen is exported via VNC the remote screen will also be garbled. However, this may not be always so. At least in an A31 screen got garbled right after returning from a text-only session (ctrl-alt-F1, cntr-alt-F7), but the VNC session previously opened on the same machine did not experience any change.

Most likely this is a problem with the ATI videochip, can people who experience this indicate which chip their machines contains?
Looking at the effected machines, this is probably an issue specific to the ATI Mobility Radeon 7500

Affected Models

Affected Operating Systems

  • all

Status

It is probably a problem of the graphics circuitry. In any case, it's a hardware problem and warranty will apply.

Solutions

You can have IBM fix the problem if your ThinkPad is still in warranty.

One reported workaround is suspending to ram after powering on and leaving it on power. This way the screen might still be fine after wakeup. The moment when you cold boot again, keep the laptop at the garbled boot screen for about 5 minutes, then do a normal reboot and press your thumbs.

The problem can also be due to bad contact on screen and/or keyboard connectors on motherboard. Try pulling out the keyboard and pushing slightly the connectors, the screen should display again correctly. If yes try puting a foam hold over the connectors and pull back the keyboard.

Depending on the ThinkPad model, running the laptop on only battery power should reduce the garbled/corrupt effect. Due to the lowered processor speed, it should generate less heat which should reduce the corruption. It helps to have a high-charge capacity battery to prevent it from happening.

In some models (At least the T40 with 9000 pro) the problem dissapear if you make an underclock. The default clock of the mobility 9000 pro is 250mhz in the core and 200mhz in the memory. if you lower the core clock to 100mhz the problem dissapear. In linux you can use a tool called rovclock to make the underclock.

Instructions for gentoo and the mobility 9000:

1) Download rovclock from this website: http://www.hasw.net/linux/ 2) Compile it 3) Copy the binary to /usr/local/bin 4) Put these lines in your /etc/conf.d/local.start

cd /usr/local/bin rovclock -c 100 -m 200

Sorry for my bad english, im only speak spanish

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I recently experienced this problem; in my case it sometimes also failed to boot at all and produced one-long-two-short-beeps.

My diagnosis was that one or more of the pins on the ATI Radeon chip had come unsoldered, such that it would make contact if the laptop was pressed or twisted a certain way, but not others. I dismantled the laptop until I could reach the chip (it's under the fan assembly, so you can leave things like the PCMCIA assembly and right ultrabay on). Pressing on different corners of the chip made it work or fail. It's a surface-mount chip with the pins underneath (BGA?), so you can't resolder it from the top OR bottom. I had to make a custom tip for my heat gun by bending some aluminum to a square slightly larger than the chip (1.25" square). 15 seconds at the 1000F setting successfully resoldered the chip for me. We'll see about long-term reliability. I hope you find this useful. Obviously I would not do this on a computer which was still under warranty, but for a computer which is not, replacing the entire system board (IBM's procedure for fixing this problem) is simply not economical.

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I experienced similar problems with a R50p model. After some investigation I found out that the screws holding down the cooler of the grafic chip were a bit loose. There are 4 bolts, two inside the case, two are fixating it from outside on the back of the case. One of the back bolts also fixates the keyboard. I tightened those 4 bolts rather hard, but not insanely hard. Because I was about to tighten those 2 inner bolts, I also tightened all the others inside the case. To avoid other tensions, I tightened the other outer case bolts rather slightly.


Also see Problem with video related system lockup II