hello everyone. i have and t61 and a t400 both are same size.
what i want is put t400's motherboard to t61 and t61's to t400. and both of them must survive after this operation.
any ideas ?

I have wondered about this before myself as several parts are interchangeable (palmrest, keyboard bezel etc).

You should take the laptops apart and compare the boards

while I don't know the answer for sure, but a question that comes to mind is "why" do you want to do this?

edit to add:
just checked and a T61 MB and structure frame seem to fit in a T400 bottom panel and vice versa

I had both side by side and they looked totally different. If you remove the palmrest and keyboard, they don't look anything alike, plus the T400 uses sata ultrabay drive, not even the drives are interchangeable.

I could be wrong, but I don't think you'll have any chance at frankenpadding these two machines, and from what I understand the palmrest isn't event he same, one of the "stand-offs" is a different length, and I know for sure the harddrive covers do not interchange. You can swap keyboards, harddrives and batteries, but not much more.

If you do somehow manage to get one installed, you'll need to replace your optical drive and your ram at least.

I have personally used T61 palmrest on T400 and even though the threaded mount of one screw had to be filed down a bit, it worked perfectly. T61 has a bit smaller touchpad also.

Take a look on miniPCI where you put WIFI it's in different place

I try to do this but it's imposible (but of cours you can cut frame and maybe it will fit.

There is a basic problem. The LCD connector is different

Yes, I'm aware of the longer "stand off" on one of them. Shortening it to make it fit is an option, but swapping the other direction would require lengthening it, or removing it altogether. Leaving it without a screw should be avoided because if someone ever did install a screw, it would likely break the part. I believe it was richk that alerted me to this.

I do know you can swap LCD screens, assuming the T400 isn't led backlit, and it might be possible to use a t400 cable in your t61 lid to get past the systemboard connector problem, but unless you have a pile of parts and want to do this for entertainment, I suggest it's a very bad idea.

However, we'd all love to know if it can be done.

ps. considering I just sold a really nice high-end t400 for less then $300, I can it worth all this effort to end up with something less then a t400 in the end. If there was some unique objective to achieve, then I'd say go for it, but if you're only trying to fix a dead system board, then I'd just get a t61 intel board and be done with it.