[Hi Gunnarh,
I had the same problem as you a few months ago. Your problem is easy to resolve. I know that my solution is really odd but this is only way. All notebooks have the same problem: contacts between memory banks and memory modules. Here's what you need to do: place your memory module in memory slot B and stick some piece of paper to make memory module closer to the motherboard, take cover on and close it with screews. I know that this is really stupid solution but this was working in my case (and not only in my case) and it will work.
Just let me know did you succeed!

Of course I tried all sorts of means, including increasing the contact pressure the way you did it - but no matter how I tried I was unsuccessful. Thus I went to the workshop to have the sockets resoldered... I really appreciate your comment and I hope that it works for a long time for you. The problem with your remedy is that you put more pressure on the socket on the connection between the memory socket and the motherboard, exactly the connection that I have resoldered, and that way you might have creep failures in one or more connection after some time. Is yours a T8100?

This is my hypothesis about the common memory errors in T8XXX:

It all happened in the era when you built your motherboard and accessories into a light plastic structure to make it a laptop. This plastic structure has a rigidity too few magnitudes more than the motherboard. This led to the consequence that the laptop could bend and flex be compressed etc. by minimal forces such as when you carry it in a flexible laptop bag or worse in your overfilled briefcase. After some thousands deformation movements (that should really have been performed in a test rig when it was developed) minor cracks would be generated here and there on the mothjerboard - but even worse for the memory socket you get stress concentrations in the soldered connections. If one of them breaks you have arrived at memory outage like the one I have described.

In the next generation of the computers referred to you built in a magnesium chassis that increased the stiffness by many magnitudes and the problem had gone. I would not be happy to hear that T9XXX have the same problem as we T8XXX owners have experienced, do you??

The T8100 was a top of the line computer in 1999 costing corresponding to round US$5500. It was really good but a stiffer structure round the electronic components would have helped it to a longer useful life.

My Toshiba Tecra was working (great) 3-4 months with the solution with paper sticks between memory modules and memory banks and then happened a strange thing: hinges get broken - I had some expirience about replacing hinges on notebooks so I get a new pair of hinges and replaced it by myself. When I had try to boot after assembling whole notebook I get nothing !?! Cpu fan is spinning, MB is recognizing CDROM (can't open it), power OK.. but nothing on the screen! I've tryed everything but I couldn't resolve this problem. So I have one Toshiba Tecra 8100 with MoBo malfunction :-(
I'm agree with your attitude of notebook problems - the main problem are notebook manufacturers. There's no spare parts for notebooks (at least in my country) or they are very (very) expensive so you can't replace malfunctioned part. On the other hand quality of ALL notebooks is miserable and beacouse of it they are enforcing us to by a new model.
I must have notebook computer (couse of my job) but I will never buy Toshiba - I will never buy anything that have sign Toshiba on it (fool me once shame on you, fool me twice shame on me).

I am having the same concern w/ my bosses Toshiba T8100.. Awhile back he had me replace the screen cause one of his kids dropped it & shattered it. Had no concerns for it being slow at that time. Then now he has me see why its running so slow. Took it home, by the way i still have it in my possession, trying to figure it out. The system is all good w/ no conflicts. The only thing that was wrong is the slot-a is not being recognized. Has no warning messages pop up. Pulled the cover off the back & it had 2-128's installed. The system is only recognizing 128. Even the bio's. Since i've been partially in it before for the screen I was thinking of disassembling it again down to the mobo & see if the solder has come loose from that slot on the mobo. The memory chip does seem to fit kinda loose when insert it. The b-slot fits a little tighter. Now i could go ahead & install 1-256 in the b slot & be done w/ it or even install a 512 as well in the b-slot & leave it be like it is. I'm planning on installing some PC133 in the slot even though it calls for PC100. This can be done as long as i don't mix up the memory speeds once i get it fixed.

Of course that memory bank contact is your problem, too. Esspecialy after that kind of stress like droping on the floor. You can resolve problem (but only temporary) by sticking a piece of paper between contacts, at first problem is always on slot A, but it is just a matter of time when the problem will expand on slot B. The only solution is replacing system board.
The other thing: I am not sure that memory module on PC133 will work on Tecra8100 at all - I know it sounds stupid but it's happening wery often on notebooks for a difference of desktop computers. Some notebooks (I don't know about Tecra) will not work with fastest memory modules.
And one thing more: you can't install one memory module of 512MB, the only way is two memorys of 256MB if you want total memory of 512MB.
And remember: Toshiba notebooks are piece od s...t!

I'll give the piece of paper a try. But the matter about the PC133 is a computer tech i know said it can be done as long as you stay w/ that same chip speed in both slots & not one PC100 in one & a PC133 in the other. But i decided to go ahead & get a 256 just to be safe. The paper must put enough pressure on the contacts so it will make a good connection, right? He did ask me if i wanted to buy it & i said i would think about it cause it is a very clean & taken care of laptop. Just does'nt have enough speed like a one w/ 1ghz or more. Thanks for that temporary fix idea. david!!

Well the paper trick did'nt help if i put it in right. i guess i'll just put in the new 256 ram & be done w/ it. Don't believe i want to tackle disasembling this laptop to see if i can fix the mobo.

I don't berlieve that you can do anything on the motherboard - it's all high integrated technologie. I've tryed and didn't get anything.
Please, let me know if you succeed to make sodimm sdram pc133 to work on this laptop beacouse I would do the same thing if that combination can work.

I've decided to replace it w/ PC100 256mb chip. Not too comfortable putting in PC133. The paper i installed i put it in the top portion on top if the chip then plugged the chip in just uderneith it.