Thinkpads Forum

My ThinkPad 600e (2645-55U) has a PII 300 MHz CPU. I have a mobile Celeron 400 MHz MMC-2 CPU and I tried installing it tonight.

When I turned the laptop on, at first I thought the install was successful. The screen turned on and displayed the correct amount of RAM with "IBM" in the top right corner and "ThinkPad" in the lower left. It made the single post beep, but never progressed. I can't get into EZSetup. It simply freezes at that point and my only option is to push the power switch.

I put the PII 300 CPU back in and everything worked again. So, I installed the Celeron again and it repeated the problem.

What am I missing?

Are you absolutely positive it is a Celeron 400 Mhz?

I am not that knowledgeable with Celerons, but if there is such a thing as a Celeron with 100 FSB, then that would be a problem. You should have PC100 RAM in order to get a CPU with 100 FSB to work.

The other issue might be L2 cache. I understand Celerons have 128 KB cache and PII 256 KB cache. But this is only an assumption.

The other thing is time: give the ThinkPad time to read the new system configuration and save it properly. I would say, disconnect the CMOS battery (RAM compartment) and connect it again after you have installed the Celeron. Wait 5 minutes before plugging the AC adapter and/or installing the battery (the big battery). Wait another 5 minutes before powering on.

Try disabling the L2 Cache before you install the 400Mhz processor. do control-d to get into the hex editor in config in BIOS and change byte 20 to 0A.

hjulian wrote:Are you absolutely positive it is a Celeron 400 Mhz?

This is the exact model. 66MHz FSB. I have the 32mb onboard RAM + 2x128mb PC100. I removed the extra RAM and that changed nothing.

It gives me no error codes...I thought the L2 cache error would create an 'error 127' message.

I'll mess with it again after I get a few more ideas.

MMC2 celeron 400MHz won't work since TP600E needs 440BX while your
CPU module is equipped with 440DX. 440DX is a subset version of 440BX
which does not support AGP bus.
http://www.intel.com/cd/channel/reselle ... /35986.htm

TP600E's video chip is Neomagic MagicMedia256A which needs AGP 1x bus.
So any 440DX based CPU modules are not compatible with TP600E.

Celeron modules with 100MHz FSB should work since they are all 440BX
based modules.

Ah, that's sort of what I expected. Thanks for the help

At least the chip was free.

the celeron 433/66 works beaut on the tp600e full cache nall.
maybe 400s have different registras or more likely dud cpu.(because theres not one mmc2 cpu the 600e didn't accept.
others that work are celeron 450-500-p3 450+(100 fsb variants with hex edit mod for error 127 post)