Thinkpads Forum

Finally found an 850 mhz cpu. Since I have minimal experience with laptops I looked up the maintenance manual. Unfortunately it's not crystal clear how to r&r the cpu. I've got a 600x (2645-9ZU). Do you disassemble from the back side or do you remove the keyboard and work from the front? Any tips from someone who has done this would be appreciated..thx

flybuddy wrote:Do you disassemble from the back side or do you remove the keyboard and work from the front?

Actually, both . The screws to be removed are on the bottom side of the laptop. If it has never been opened, or the previous owner(s) were tidy enough, the screws are covered with a black plastic disk. The screws to be removed all have 'arrows' pointing at them. The diagrams in the HMM should tell you exactly which ones to remove. Pay particular attention to the 'long' screws as there are two different lengths. To remember which one goes where, the length of the 'arrow' next to the screw hole is indicative of the length of the screw that goes there.

Once all of the screws have been removed from the bottom (about 12 of them if I remember right), turn the laptop right side up and remove the keyboard. Be careful when reaching in to disconnect the ribbon cables from the keyboard to the Sub Card. Once you have the keyboard out of the way, the CPU is a snap.

Ray,

You forgot to mention the screw that is located between the IBM thinkpad logo and the 600X plate that is also covered with a black disk. That also needs to be removed.

cmarti wrote:Ray,

You forgot to mention the screw that is located between the IBM thinkpad logo and the 600X plate that is also covered with a black disk.

AH! You're right! Forgot about that one! It's been a little while since I took apart one of my 600s, although one more system is going under the knife (Dremel) in a bit for an external antenna mod.

Thx guys, that's a big help. I'm still waiting for the new cpu to arrive and I didn't want to take the 600x apart till I've got it in hand.

flybuddy wrote:Thx guys, that's a big help. I'm still waiting for the new cpu to arrive and I didn't want to take the 600x apart till I've got it in hand.

2 Hints:


Be VERY careful removing the keyboard. There are 2 cables attached to the motherbaord. Take great care and remove the cables carefully or they will pull out of the MB connectors and then you'll be spending $25 for a new keyboard..

When you remove the CPU remove ALL the CPU and fan screws first, and then remove the fan.. That must be removed first before the CPU daughter board can be lifted out...

Good Luck

Don't discard your old CPU. I made this upgrade and had intermittent problems when booting - not consistently enough to be absolutely certain that that the CPU was the problem, but certainly noticeable. The 600X that I use now still has its original 650MHz CPU.

Edward Mendelson wrote:Don't discard your old CPU. I made this upgrade and had intermittent problems when booting - not consistently enough to be absolutely certain that that the CPU was the problem, but certainly noticeable. The 600X that I use now still has its original 650MHz CPU.

When you did the upgrade, were there any system changes or software loads needed?? What kind of boot problems did you have and what OS were you using?? thx

No changes except the new chip; the system simply wouldn't boot some times - it would boot on a second or third try. I was running Win2K - but the failure to boot occurred before the OS even began to load. It was clearly a hardware, not a software problem. The performance increase didn't seem to be worth the effort. Your results may be completely different, of course!

Strange, Mine boots perfect everytime i am sure the cpu you got must have a problem, in my case thanks god is working flawless!!

Do you recommend using thermal paste?

flybuddy wrote:Do you recommend using thermal paste?

Only if you remove the thermal pad.

It came today (priority mail-even though we were in middle of tropical storm--guess not every mailman is like Newman). Anyhow, took better part of an hour to install (thx for the advice). Booted right up (without screws) and running normal with no glitches. CPU tests come up at 840 mhz. (booted up normal after the screws installed also)

flybuddy wrote:It came today (priority mail-even though we were in middle of tropical storm--guess not every mailman is like Newman). Anyhow, took better part of an hour to install (thx for the advice). Booted right up (without screws) and running normal with no glitches. CPU tests come up at 840 mhz. (booted up normal after the screws installed also)

Did you use the thermal paste?

Can you do an exercise? Please turn on the pc with the ac adapter then after it is all running measure the cpu speed and after that remove the ac adapter and measure againg the speed do you see any difference does it decrease the speed to 700mhz?

And if you are able do the same exercise but turning on the lappy withuot the ac adapter on batteries. To see if the cpu step up from 700mhz to 850mhz when you re-connect the ac adapter.

OK, it's working like this...Start it on AC and it's 840, if you pull the ac adapter out, it stays at 840. Reverse holds true on battery, starts at 692, and stays there even if you connect power.

flybuddy,

So all the 600X that have been upgraded to 850mhz have the same behavior.

Thanks..