Memory experiments on TP240 (with pics)

[matasj]

I don't know if anyone has done it or not, but I successfully re-soldered the onboard RAM - I switched 64Mbit with 256Mbit chips. However, the onboard RAM is recognised as if it was with 128Mbit chips and this is because one of the pins is not connected to anything and that pin is used for register ROW-SHIFT.

Here are some PICS:


http://images110.fotki.com/v615/photos/ ... 732-vi.jpg
http://images56.fotki.com/v168/photos/5 ... 739-vi.jpg
http://images56.fotki.com/v168/photos/5 ... 758-vi.jpg
http://images57.fotki.com/v496/photos/5 ... 818-vi.jpg
http://images58.fotki.com/v510/photos/5 ... 835-vi.jpg

Only with onboard memory:
http://images58.fotki.com/v513/photos/5 ... 859-vi.jpg

With either additional 128MB PC100 or 256MB PC100 RAM:
http://images12.fotki.com/v616/photos/5 ... 924-vi.jpg
http://images115.fotki.com/v607/photos/ ... 135-vi.jpg

I stripped the chips of an IBM SDRAM board (256MB PC133). I was thinking about doing the same to my 240X, but it only has 4 chips installed and they are already 128Mbit.

P.S. This is the first time i POST anything here, I think it is not going to be the last...

P.P.S I wish for a MODs forum...

Admin edit: Welcome to the forum! We have a policy of not allowing inline images >50KB in any of the boards other than "Pictures of your ThinkPad & desk setup" . I've left the first one intact since this is an interesting modification.[/b]

[Tasurinchi]

Wow... Good job! Is the 240 working without problems after this?

[matasj]

It loads WIN98, doesn't crash. I haven't tried any of memtests yet.

[kenzking]

That is very impressive. I would not attempt to do that kind of soldering work myself.

Any tips you have?

[matasj]

If you are going to desolder the chips using hot air - be sure to set the air flow to the lowest setting or you might end up blowing off capacitors and resistors. One of my friends suggested to cut the chips off and then only desolder the pins - bit by bit. I've used a gas soldering iron without the tip to desolder. This kind of job really requires a lot of patience so firstly I'd recommend to try your skills on old SDRAM boards - desoldering and soldering back on and seeing if it works. You also have to keep in mind that these chips do not like heat - overheating damages the chips unrepairable.