T40 Problems. Or is it a T42? You decide. [WARNING: 2 PICS]

[Fakenjones]

Hey guys,

So I've had a T40/T42 for quite some time. And I have some questions regarding a problem it's having.
The labels identify it as a T40. But, the model number sticker identifies it as a T42. Same with CPU-Z.

Details of the Machine
Model 2373-4WU/K2U --> first is sticker, 2nd is what CPU-Z reads.
Windows XP Pro SP3
Intel 1.6GHz Pentium Mobile
512MB PC2700 RAM
80GB HDD
ATI Mobility Radeon 7500 32MB
DVD/CD-RW drive
2 USB Ports, S-Video, VGA
Modem/Ethernet
Trackpoint, Trackpad

Brief History
Initially it had the GPU issue. Went into repair. Came back fine. Then I gave it to a family member to use.
Then it again had GPU issue. Decided to replace motherboard. Came back fine. Family member kept using it.
After a few months frequent errors/crashes were reported to me. The laptop was soon declared completely dead.
Me and the family member both assumed that the GPU error had re-occurred and wasn't worth repairing again.
At this point, neither I nor the family member had time to inspect the laptop properly so it lay dead for oh... ~1-2yrs.

The Present Situation
This week we decided to finally sell it. Either for parts or as a whole.
Before that, we wanted to investigate the problem properly. So we could tell the buyer what to expect.
Here is what we found:

EDIT: We also found that though the machine is labeled T40 on the screen, the type sticker below, and the type identified from the CPU-Z software both identify the machine as T42. So I'm not really sure what's happening there. It could be causing some of the problem.

Problem Symptoms
Mostly
-does not boot
-displays Blank Screen with HDD & battery light on
-beeps 4 short beeps 4 times
Sometimes
-gets stuck at IBM screen
-gets stuck at Windows loading screen
-gets stuck 10 seconds into logging in/or waiting at login

Error Identification
Apparently the above symptoms are interpreted as a "System board Security chip error"
See here for more details: http://www-307.ibm.com/pc/support/site. ... 46018.html

The *Random* Solution
As I really had no idea what that error description meant, I tried some good old trial and error. And... I found:
- If I left the RAM installed under the keyboard, the problems occurred as listed above
- If I moved the RAM to the back of the laptop, the problems stopped completely!
So naturally I moved my sole chip of RAM to the back and now the computer works fine.

My Questions & Request for Your Expertise
But now I want to find out
1) Why the RAM slot under the keyboard causes the error? Defective? Unclean connector? Something else?
2) How can I fix this? Or is it even fixable? Or is it simply some software error that can go away with a reformat?
3) If I'm planning to sell this computer anyway (likely on these forums), is it worth fixing it in terms of cost...
----> obviously number 3 is subjective, but just wondering your opinion on it as well.

Picture of the Guilty RAM Slot



Thanks (in advance) for all the help and comments.
Sincerely,
Faken Jones

[poshgeordie]

Hi Faken

If there's an error when the RAM is in the top slot, then there may be soldering problem with the slot pins - like with the T30's. If you're OK with using the bottom slot only then stick with that.

Regarding the board type I'd suggest removing the fan (you'll have to renew the heatsink compound before refitting it) and checking the part number:

If it's a slower Banias chip typically fitted to T40's then it will be SL6FA, but if it's a faster Dothan one (typically fitted to T42's) it will be SL7EG.

I'm making a big generalisation here but it may give some clues.

[RealBlackStuff]

When you open the RAM slot at the bottom, remove the ram, what motherboard P/N or FRU do you find on the white label there?
That may help us determine more.

[Fakenjones]

OK so the RAM slot at the bottom has this on the first sticker:

FRU/PN: 27K9984
IIPC P26R8207 (under a barcode)


There's also another sticker with a large string of letters/numbers.
There's also a third sticker right below it, but I think that's just that MAC address.
Let me know if you need any of that information.

Thanks.

[poshgeordie]

That's a T42 motheboard and is listed in a couple of places as having specs: T42 32MB,ATI RADEON7500,W/FINGER SECURITY.

@RBS checked the BR mobo list and it looks like it's similar to 27K9910 and ties up with the model Type 2373-K2U - maybe worth adding (how many board models ARE there!)?

[Fakenjones]

Hi Faken

If there's an error when the RAM is in the top slot, then there may be soldering problem with the slot pins - like with the T30's. If you're OK with using the bottom slot only then stick with that.

Regarding the board type I'd suggest removing the fan (you'll have to renew the heatsink compound before refitting it) and checking the part number:

If it's a slower Banias chip typically fitted to T40's then it will be SL6FA, but if it's a faster Dothan one (typically fitted to T42's) it will be SL7EG.

I'm making a big generalisation here but it may give some clues.

Hey poshgeordie,

Thanks for the response. It may be a soldering problem indeed considering the random motherboard history of the laptop. However I'm intending it for sale anyway, and a soldering problem is not worth the effort to fix on my end. So I'll just stick to the back slot for now.

When you open the RAM slot at the bottom, remove the ram, what motherboard P/N or FRU do you find on the white label there?
That may help us determine more.

Thanks. I didn't know that's where the motherboard FRU, P/N could be found. I'm gona start checking my laptops more thoroughly. I've bought a few from a local dealer so it would be good to know if there's some part swapping going on.

That's a T42 motheboard and is listed in a couple of places as having specs: T42 32MB,ATI RADEON7500,W/FINGER SECURITY.

@RBS checked the BR mobo list and it looks like it's similar to 27K9910 and ties up with the model Type 2373-K2U - maybe worth adding (how many board models ARE there!)?

Yep I've come to the conclusion that it's a T42 as well. By the sticker indicating type of the old machine, FRU/PN of the new motherboard, and the CPU-Z reading of the new motherboard, and by your finds above.

This then begs the question: why is it labeled as a T40 on the lcd screen near the bevel. Maybe the LCD panel was replaced at some point? And the T42 laptop was mistakenly identified as a T40 from then on? Who knows...

So what do you guys think this thing is worth?

[poshgeordie]

This then begs the question: why is it labeled as a T40 on the lcd screen near the bevel. Maybe the LCD panel was replaced at some point? And the T42 laptop was mistakenly identified as a T40 from then on? Who knows...

The original display will have been swapped out for a T40 one, or the t42 display bezel swapped out for a T40 one. It's not uncommon where there are LCD / Inverter / LCD Cable problems.

Value? I only fix them so have no idea!

[FTC]

Hi,

Although I also tend to think that the problem will probably be a defective slot soldering,... it still *could* be a problem with the RAM dimm. Note that both slots are not electrically the same thing.. data path lengths varies and impedances,.. etc are not identical so a given dimm could work OK in one case and not in the other place. I have found some cases of apparently bad slots working fine with some dimms and not with others. This is more frequent when both dimms are installed because of timing issues, but just don't discard the possibility of still having both slots fine.

[Fakenjones]

Hey FTC:

That's interesting. Never considered that possibility. But it's too late to test it now. Live and learn I guess.

@ Rest:

Thanks for all the responses. The laptop has been sold. It was quite capable in its time and served us well.