R61 Type 7738-CTO 14.1" 1400x900 Screen corruption

Hi,

I picked up a used 7738-CTO on ebay. Since it's a CTO here are some specs:
T7300
3 GB
Intel GMA X3100
14.1" 1400x900
webcam
bluetooth
firewire
fingerprint reader
Intel 4965AGN WiFi

It arrived in good but not pristine condition. I ran memtest86+, Hitachi hard drive fitness test, and PC Doctor tests, all passed. I didn't find any dead pixels. Satisfied that it was in good working order, I did the following:

1. Cleaned keyboard and plastics with cotton cloth moistened with isopropyl alcohol.
2. Cleaned screen with microfiber cloth moistened with wally world no-glare lens cleaner, "non-alcohol formula".
3. Swapped in a Thinkpad (Atheros) 11a/b/g WiFi card from a Type 8932 15.4" R61. Followed procedure in Hardware Maintenance Manual, which involves removing the palmrest and keyboard. I didn't unplug the palmrest, just tilted it up so could remove the keyboard (which I did unplug). Used a ground strap while had machine open.
4. Vacuumed dust out of the fan using brush attachment on top of fan, and plastic radiator (high speed) attachment on vents.
5. Vacuumed dust out of various other interior spaces using the plastic radiator attachment.

All appeared fine after this.

Next I installed Windows XP 32-bit, Norton Internet Security 2009, MSIE 8 and Firefox. No problems.

A couple of hours later I installed the XP SP3 update I'd downloaded a year ago. At some point not long after installing SP3, I noticed the taskbar looked weird:



And the bottom 20 pixels or so have been messed up ever since. They don't always look the same:


Running Memtest86+


White screen (PC Doctor)


Black screen (PC Doctor)


Flashing the BIOS

The pattern changes over time when just sitting idle in XP or in BIOS Setup. But I can't make the pattern change by:

• Changing the angle of the screen, from flat to nearly closed.
• Flexing / pushing the LCD ribbon cable (with keyboard moved out of the way).
• Pushing on the LCD ribbon cable connector.
• Pushing on keyboard connector.
• Moving keyboard around (flexing its ribbon cable).
• Pressing on screen bezel.
• Pressing on back of screen housing, warping it very slightly.
• Pressing on heatsink covering the north bridge.

Here is a close-up of bottom left of XP teletubbie screen (with vertical taskbar on left). The single row of bright pixels at the top of the corrupted band does change when I drag windows around -- it seems to mirror the screen's top row. The rest of the band seems only loosely related to what's on the screen (see black blotches under some taskbar items in the first image) but doesn't change when I drag windows around.

Googled turned up this post about a similar problem. I have tried:

• Removed and re-seated the LCD ribbon cable connector (twice).
• Un-plugged and re-plugged keyboard.
• Flashed the BIOS to older 2.14 then back to latest 2.26.

None of the above appeared to change anything.

Everything else on the machine works. DVI video to external monitor is fine. The Atheros WiFi card I swapped in works. I re-ran Memtest86+ and PC Doctor tests and they all still pass (except for the interactive video ones!)

Some ideas of possible causes:

1. Pinched LCD ribbon cable? On this machine the metal bracket that secures the LCD ribbon cable motherboard connector to the frame has a step down where it attaches to the WiFi card support. The step in the bracket causes the edge of the LCD ribbon cable to be bent down. When I tightened the left WiFi card screw, which doubles as the right LCD ribbon cable bracket screw, I wonder if I pinched the ribbon cable? Or maybe tightening the keyboard pinched the ribbon cable?
2. Hosed LCD? I did clean around the edges of the screen. Maybe some cleaning fluid worked its way behind the screen bezel and wreaked havoc?
3. Dust shorting something out? Vacuuming the inside caused some dust to shift around, maybe to unfortunate locations?
4. Shock damage? If UPS dropped the ThinkPad (shipped in its original box) on its way to me?
5. XP SP3 killed my ThinkPad? (!)
6. Pre-existing condition? Seller said everything worked fine as far as they could tell.
7. Something else?

Would really appreciate troubleshooting tips from those of you with experience with such problems.

I'd like to fix the problem myself if possible (system is out of warranty). I'll spend some money if I have to, but don't want to replace the screen only to find the problem is something else.

Sorry for the length of this post, wanted to give details that might suggest a cause. And hopefully a fix!

Thanks,
Frank

 

Honestly, if it were me I'd ask for my money back.

 

Things to try:

1) The fact that the problem started with the XP SP3 update implies a driver corruption. Try booting into Safe mode (use F8 key after POST) and see if the screen is corrupted. If not, implies video driver problem. Go to intel.com and get their latest X3100 driver.

2) If it is not driver problem, I would pull off palmrest and reseat the memory modules.

3) I have seen some R61 with thermal issues. If the bottom of the ThinkPad feels hot, google tpfancontrol. Download and install this utility

 

I highly doubt this problem is a software issues, it is most likely a hardware issue of some sort.

Unless you have spare LCD, cables and motherboard, this sort of problem is hard to determine with 100% accuracy. I would just get it returned to the ebay seller as a DOA.

Oh, you could try to re update the bios, but i doubt that will help you to any great extent. The T7300 in a R61 14.1 inch shouldn't cause much problem, i have one in my T61 14.1, and it is just fine.

 

Thank you all for your help.

With apologies to Jimmy Buffett, "Some people claim that there's ebay to blame... But I think... Hell it could be my fault." The seller has 100% ebay rep over 8 years, and says he never saw this problem during 1-2 years of using the system. I have no reason to doubt him, and in fact the screen looked fine when I first started using the system.

The somewhat puzzling thing is that the screen was fine *after* I'd finished messing with the system, only becoming corrupted ~2 hours of use later. Those 2 hours were spent sitting on a desk during OS and software installation.

I'm left to think that either UPS or I did something to the system that caused this delayed fault to appear. I have no evidence other than the display fault itself against UPS. The ThinkPad shipped in its original box, with original foam inserts. No signs of damage to the box.

That leaves me.

I'm still just trying to figure out the most likely cause of the problem:

I re-ran the PC-Doctor for DOS tests multiple times in a row:

• System Board tests passed 10 times in a row.
• Video Adapter tests passed 5 times in a row.
• Protected Mode Memory tests passed 5 times in a row.

Other things I tried today, with no change in symptoms:

• Ran TVSU to update all drivers.
• Loaded BIOS defaults.
• Removed BIOS backup battery for 10 minutes and shorted terminals to clear CMOS.
• Discharged static electricity: With battery and AC removed, press power button 10 times in a row at 1s intervals, the press and hold it for 30s.
• Removed and re-seated palm rest connector.
• Removed 2 DIMMs and tried each singly in slot 0.
• Ran mprime torture test for about 2 hours cumulative with no errors.

I'm thinking that lead_org is right, there must be a hardware fault in one or more of the LCD, LCD ribbon cable, or motherboard.

LCD
I've read and heard everywhere that you're not supposed to spray cleaner directly on the LCD. What would happen if you did, and it ran down between the screen and the bottom bezel? Could that cause a delayed screen fault like I'm seeing?

Another possibility that seems unlikely is that UPS jarred something loose and it didn't fully detach until many hours later... while sitting motionless on my desk...!


LCD Ribbon Cable
This seems the most likely culprit, since I was poking around in its vicinity, removing one of the screws that holds the connector retaining bracket, and pushing the WiFi antenna wires in/out of the clip attached to that bracket.

Should I try spraying the connector with contact cleaner?

How easy is it to crush the ribbon cable by over-tightening the bracket retaining screw?


Motherboard
All the passed PC-Doctor tests and perfectly functioning external video make me think the motherboard is ok. But I suppose there could be a fault in the circuits between the north bridge and the LCD connector.


I'll probably get a new LCD ribbon cable and try installing that first. Unless you think there's a better course of action?

Thanks!
-Frank

 

Since the cable is the cheapest part it's usually the best place to start.

 

Give everything a good clean in terms of connectors, i am not sure whether you want to disassemble your other good laptops of similar sort, and use their parts for troubleshooting.

 

I took apart the screen assembly and tried unplugging / re-plugging the cable at the LCD. Neither that nor poking at the LCD cable changed the symptoms. So I replaced the LCD, and that fixed the problem.

FYI, here is a somewhat crummy closeup picture of the LCD cable at the screen end:


There are only 30 pins on the connector. The cable carries the video signal from the system board to the LCD using the FPD-Link signaling standard. (Inconveniently, there is no standard connector pinout, so the cable wiring depends on the exact LCD used.)

National Semiconductor has a nice page on the history of FPD-Link, with comparisons to DVI. They say that "A 6-bit single pixel application using an... FPD-Link interface requires 3 data pairs plus clock." Looking closely at the R61's LCD cable, there are 8 trace triplets at the right side, plus 1 larger trace triplet to their left, plus 1 more trace. I've written the LCD manufacturer (Samsung) and asked for a connector pinout, because I'm curious. But at this point I'm guessing that each trace triplet is a forward wire + middle ground wire + return wire.

Bottom line point I wanted to make is that the video signal is transmitted over just a few wires in the cable in a complex, serial form. A problem with one or more of those wires should result in visible corruption all over the LCD; it isn't like a single wire maps to a given physical LCD location.

So in case anyone experiences problems like I did, with video working fine on an external monitor, and everything looking fine everywhere but in a small area of the ThinkPad's screen, you can be nearly certain the problem is the LCD itself.