A31p screen glitches

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bdemchak · #1 Post by **bdemchak** » Mon Dec 18, 2006 2:06 pm

Hi ...

... I'm hoping for some information so I can make a good decision regarding my poor A31p.

The problem is a glitchy screen ... both on the LCD and the external monitor. It looks like certain video banks are being written (or read) corrupted. For the most part, the screen is clean. However, some bitmaps (e.g., icons on a button bar, or a calendar on the desktop) come out with horizontal glitch lines ... generally purple.

When I power up the PC, I get *a lot* of vertical glitches ... after the boot, though, they're horizontal, and they're confined to bitmap overlays.

So ... it looks like there's a bad bank. (Maybe it's spreading to other banks??)

This is my second A31p, and the second set of identical symptoms.

Does anyone know what's going on here?? It sounds like a motherboard problem ... and I'm guessing that there is some weak part (video controller or memory) that simply doesn't stand the test of time.

In case anyone's interested, an example is in the lower right corner (the calendar) in the screen shot: http://www.tpsoft.com/a31p_glitch.jpg

And I'm especially interested in what anyone might think the implications would be for the rest of the unit's functionality.

Wadddy think??

Thanks!

#2 Post by **rkawakami** » Mon Dec 18, 2006 2:15 pm

Welcome to thinkpads.com!

Just a thought... try changing your background/desktop image to "none" (i.e., black screen) and see what happens. I'll ask one of the guys in our applications group today and see what he says (I work for a company that had DRAMs going into video graphics cards so this is something he should be familiar with).

bdemchak · #3 Post by **bdemchak** » Mon Dec 18, 2006 2:48 pm

Thanks ...

I set the screen saver to blank, and there was total black. I set it to beziers, and the screen drew just fine.

This supports the idea that the corruption is coming from a video bank that's the source for BitBlt operations ... so it seems to me.

Whether this is actually the true explanation is another story ... and I don't really understand the larger implications.

#4 Post by **rkawakami** » Mon Dec 18, 2006 7:56 pm

My boss says he's seen problems with some vendor boards that ultimately traced back to bad addressing which caused problems like this, although it affected the entire screen, not just a small window.

Can I assume from the picture you supplied that you are running 32-bit color? If so, try backing down the color depth and see if the same thing occurs. If it is a problem with addressing a different bank or portion of the video memory then it might be possible to avoid that section of memory with a lower color bit setting. This of course is no "cure". For that, you're probably looking at a motherboard replacement. It could be a similar problem to what is mentioned in this thread:

http://forum.thinkpads.com/viewtopic.ph ... 779#231779

This post picks up the conversation about garbled video on a T42 and talks about how somebody got the video chip re-soldered on his motherboard. Note: this type of fix could cause MORE damage or problems!

Question: Do you have a copy of PC Doctor installed on your system? If so, try running the video diagnostics.

bdemchak · #5 Post by **bdemchak** » Tue Dec 19, 2006 11:02 am

he he ... yep ... changing the color depth changes the glitching. It moves it out of the confined BLT and redistributes it over the whole screen.

I'm afraid I don't have PC Doctor on this system ... I might have it elsewhere ... I'll look.

In the meantime, I think we can blame this on the motherboard. The question that comes up next is where the problem spreads from here. It sounds like a hard question to answer since we're not sure exactly where the problem started. Correct??

I'm afraid I don't have enough interest and desperation to try the solder operation. I'm just not that brave or skilled.

Side issue: in low power situations (i.e., without AC, or when system is just powering on) the screen takes a red tint. Have you heard of this problem ... might this be related to the motherboard issue ... what could be the cause and meaning of the problem??

Thanks!!

#6 Post by **rkawakami** » Tue Dec 19, 2006 12:52 pm

bdemchak wrote:he he ... yep ... changing the color depth changes the glitching. It moves it out of the confined BLT and redistributes it over the whole screen.

Ouch! Well, that seems to confirm what my boss said about some of the video boards he and his techs have seen.

bdemchak wrote:I'm afraid I don't have PC Doctor on this system ... I might have it elsewhere ... I'll look.

You can pick up a copy from IBM/Lenovo at this link:

HMM for A3x/A3xp

bdemchak wrote:It sounds like a hard question to answer since we're not sure exactly where the problem started. Correct??

Yes, but I would bet that the problem is due to a bad connection of the video graphics chip. Those components are huge compared to the rest of the ICs on the motherboard. Chassis flex will affect them more (and earlier) than other parts on the board.

bdemchak wrote:Side issue: in low power situations (i.e., without AC, or when system is just powering on) the screen takes a red tint.

If the red/pink tint is present each time you power on the system cold (i.e., it's been sitting off for at least 10 or 15 minutes), then I would say what you are looking at is your backlight (CCFL) inside the LCD panel reaching the end of its life. There is a (small) chance that the inverter board is the problem. If you manually turn down the brightness (Fn+End) to the lowest setting, does the screen go from white to pink? If so, then you may have a weak inverter. For all the problems I have personally seen with the Thinkpads I've bought, if the problem is with the inverter, you get NO light. It either works, or it doesn't. The reddish screen can only be fixed by replacing the LCD panel or if you are brave, just the backlight.

bdemchak · #7 Post by **bdemchak** » Thu Dec 21, 2006 11:39 am

I think you are right on ... on all accounts.

The pink only occurs on power up, and does not occur when I turn down the brightness. It *does* occur on battery, and does not go away ... I'm not sure how that figures into the analysis.

As for the system board prognosis (and the A31p in general), it sounds like all of this is approaching more a labor of love (like a '57 Chevy). While I'm in no hurry to discontinue my use of the A31p, it looks like the entire population is fading on its own. As attractive as a Z61p sounds, it also involves quite an investment. Stretching the A31p a bit longer would be my choice. Time will tell.

(Thanks for your help!)

A31p screen glitches

A31p screen glitches

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