A31p - XGA instead UXGA

[palabdul]

Hi,

Matrix in my A31p is borken. I need to buy new matrix and i have dilemma. XGA matrix is much cheaper than UXGA but i don`t know will it work properly. What to look for when looking for a XGA matrix ?

[ajkula66]

Welcome to the forum!

If you're going the XGA route, you'll also have to change the cable and inverter.

FWIW, any UXGA LCD from later models (T42p, T43p, R50p) will work in your A31p with your present cable and inverter.

Good luck.

[harvester]

FWIW, any UXGA LCD from later models (T42p, T43p, R50p) will work in your A31p with your present cable and inverter.

If my inverter is suspect, would the UXGA LCDs work with their specified inverters, and would their cables work as well?

[ajkula66]

@harvester:

What exactly leads you to believe that your machine has an inverter problem?

[harvester]

I suspect the inverter because the video is only displayed for a few seconds, then drops to an extremely low level and the A31 concerned halted did not boot. If that is a symptom of backlight failure then I stand corrected. I found it odd that the boot process halted, so i guessed "most complex part electrically nearest the system board".

Replaced entire screen assembly, adventures detailed in this thread:

http://forum.thinkpads.com/viewtopic.php?f=5&t=82178

All is well now except that the LCD (from a well-used organ donor) is rather washed out looking so I'd like to know what replacement parts will fit and function properly.

Even though I just bought a refurb T61, the A31 runs Ubuntu nicely with 2GB RAM and an 80GB hard drive. It served well for years so I don't mind fixing it up.

[ajkula66]

Two things can be in play here, a bad backlight or a failing board.

Was your screen reddish/pinkish on initial boot prior to this last episode?

[harvester]

No pinkish screen, worked fine until malfunction. Brief display when attempting to boot is not pinkish.

Thanks for the reply. It's furthering my education.

[ajkula66]

How's the external display?

[harvester]

The (vintage 1998 as a guess) old Dell CRT I have won't function with the A31 or the A31P system board. Works fine with various desktops. I have an LCD to test with, but I have to retrieve it from a machine shop where I loaned it out...

The same system board (A31) is working fine with an A31P LCD, so the problem is isolated to the old A31 components I removed as a unit when I swapped screens.

It's kind of neat because I'd have never guessed a bad screen component (whatever that may be) would halt the boot process until I saw it happen.

The A31/A31P parts are happily functioning so I'm left with a spare, malfunctioning screen I'm curious to troubleshoot (I'll slave it to the spare system board and keyboard for testing). Inverter is PN 26P8301, FRU 26P8132.

[schen]

This is beginning to sound suspiciously like a detaching GPU. Even an old circa 1998 monitor should give you the VGA output that the boot process displays. That is, as long as you have the Fn+F7 combo pressed too give a signal to the HD15 connection.

Although the detached GPU is more common in the ATI chipped R5x and T4x boards, it's not unknown in the A31 either. It can cause machines to not boot as well as not give a video output. There are a variety of ways that it presents. I have an A31p that gives garbled output to the LCD, but is fine from external signal.

[harvester]

System board functions fine after display swap. Booted many times to be sure.