t23 memory upgrade issue

[timski]

I have used my T23 for years with 2 x 256 Mb memory modules. Recently I purchased 2 modules that are 512 Mb. I started getting blue screens using the two 512 mb modules together, and either one of them alone. One of them is a brand new Kingston module matched to the T23, the other an IBM module.

When I go back to the 2 modules that are 256 Mb, seems there's no problem.

Blue screens include irql_less_than_or_not_equal and memory_management.

I have upgraded the BIOS. The machine is long out of warranty. Any ideas?

Thanks!

[rkawakami]

Welcome to thinkpads.com!

Can you provide any part numbers from both modules so that we can determine if what you are using is correct? The T23 requires PC133 memory so let's verify that first.

Memory module issues can usually be confirmed by running a diagnostic program which checks each byte for proper operation. One such program is memtest86+ and is available from here:

http://www.memtest.org/

Go to the download section and grab a version that you can use (.ISO if you can burn a CD or floppy if you have a diskette drive). Create the media and then boot the system from it. The diagnostic will automatically start running. A 512MB module takes about 45 minutes in a T23 to complete one pass through all of the different tests. Test one 512MB module at a time, moving it from one slot to the other and repeating the tests. If there are any errors, you will see red lines displayed in the lower half of the screen. Repeat the same sequence with the second module. After about 3 hours you should have an idea if one or both modules are bad or if you have a problem with one particular memory slot.

[Kaervak]

I also highly recommend running Memtest on it. In my experience that's the best way to determine if a system is having memory problems. Other things to check, are the pins on the DIMMs clean, are the DIMM sockets clean, anything possibly stuck inside the DIMM sockets? Give everything a good run through just to be sureand let us know how it turns out.

[timski]

Thanks very much. I have run memtest86 and pcdoctor, no errors. But just now my beloved T23 froze with the 2 x 256 Mb modules, so that blows my theory out of the tub.

I will re-run memtest and pcdoctor and post the results.

Thanks again --

Oh, part numbers:

IBM 512: FRU: 19k4657
Kingston 512: FRU:39P7288 (2 of these right now, one on loan from Kingston under warranty)

The 256 MB modules:
IBM: FRU:19k4655 (1 Infineon and 1 Nanya

Freezes and blue screens happen anywhere from a few minutes after powering on to several hours.

Sockets look clean, I'll start running the memtest on the 512 modules. Thanks!

[rkawakami]

If all of the memory checks come back negative, then I'd say there's something physically wrong with your disk drive or you may have some corrupted software (video driver, for example). Has there been any recent changes along those lines?

[timski]

Here's an update: I ran memtest86 on all 3 of the 512 Mb modules that I have at the moment. All tested fine in the back memory socket (closest to the screen), and if they were placed in the memory socket closest to the front of the machine, the machine would not boot up. That sounds like a clue (!). If there is a module in both slots, it will boot up and the properties tab will show 1 gig of memory, but it looks like there's a serious problem with the front memory socket.

Can I repair or replace the memory sockets for less than a new computer? Will this do the trick, do you think?

Thanks --

[rkawakami]

On the T23 the memory sockets are actually one piece. It is surface mounted (no pins going through the motherboard) and hard to get to the individual leads if you are thinking about re-soldering them. The best thing I can suggest is to try to clean the contacts on both the modules and socket. The modules can be cleaned with a cotton swab dipped in isopropyl alcohol. In a pinch, you can also use a pencil eraser across the "fingers". Be sure to do both sides as they are different signals.

The socket is much harder to do. You can try using a new, clean toothbrush. I would not use any kind of solvent as that might eat at the bristles of the toothbrush. If you can find a thin, lint-free cloth, you could dip a corner of it in alcohol and run it along the contacts inside the socket. Allow everything to dry completely before installing the modules and firing up the system.

If this does not cure your memory problem, then I'm afraid that the only solution is a motherboard swap. That can entail more trouble than what it's worth if you have not performed this operation before. Of course the easiest thing to do is buy a complete, stripped down, working base and transfer the LCD, memory, hard drive, ethernet and MiniPCI boards and keyboard/bezel.

[Robbyrobot]

All tested fine in the back memory socket (closest to the screen), and if they were placed in the memory socket closest to the front of the machine, the machine would not boot up.

Does that apply to all the modules? I had a 128 MB module for a 600X that would only work properly (memtest) in one of the two sockets. Reason unknown... other modules would work properly in both sockets.

[timski]

Thanks, Ray, and others for your replies. Looks like one memory socket is dead no matter what module goes into it, and cleaning it doesn't seem to help.

I can use one 512 mb module in the other socket, and at least not get the blue screens and freezes.

I may look for a motherboard or working base on Ebay if I'm feeling adventurous. At least it appears we have found the problem and can avoid the the crashes.

Thanks, all --

[timski]

Well I spoke too soon. The computer has frozen twice now with a tested memory module in the "good" socket. Back to square one, I guess, though the bad socket is still bad. Sheesh.