R52 and Pentium M 735A SL8BA

[sego]

Hallo,

Last december, my T40 died because of the "flexing-issue". I decided to upgrade to an R52 Mainboard ( with Intel GPU for good reason ) instead of buying a new cheap notebook.
First of all I tried to use my old 1,5GHz Banias. It failed. With the Banias CPU the notebook starts, but the display keeps black. No beeping, just nothing.
I wanted to do the pinmod, so I bought a Pentium M 735A CPU. 735A, because I wanted a stepping as new as possible. Usually these CPUs have more "reserve" for OC.
But with this CPU, it was the same. Start - Blackscreen ... No beeping etc. ...
I started to think that the board had flexing, too.
One guy in the german thinkpad-forum said that in Sonoma Boards only 533MHz CPUs work properly and very few others like the older 735 SL7EP. So I bought a Pentium M 750 and - it worked.
I also tried a bios-upgrade to 1.29, but it´s still the same. Neither the Banias nor the 735A (SL8BA) start in the Sonoma R52 Mainboard.
In this forum here I read that "underclocker" got the SL8BA working in a T43 Mainboard: http://forum.thinkpads.com/viewtopic.ph ... ilit=sl8ba
How is this possible? I was thinking that this could be a "whitelist-issue" like it is with wlan cards without fru...

[sjthinkpader]

Yes, 533mhz FSB CPU like the 750 is needed for R52.

[underclocker]

Assuming the CPU's are OK and were installed properly, I would say that the issue could be related to the version of R52 mobo that you used. There were at least two versions of the Intel GPU R52 mobo, one that came with the Celeron CPU and one that came with Pentium M CPU's. I do not believe that either was the exact one from the T43. The one with the Celeron CPU used a different Intel chipset and did not "officially" support Pentium M CPU's - although I found that it worked fine with lower speed 533MHz bus Pentium M's - like the one you ultimately used.

I think you can check the exact part number of your mobo, from the bottom side memory slot area, to see which one you have (search the HMM or www.IBM.com or Google).

[fasterbybike]

I agree with what underclocker says. My R52 comes with a 400MHz Pentium 725A. The type is 1858.

The hardware maintenance manual lists a variety of Pentium M CPUs.

The CPU model numbers that end in "0" are 533 MHz and the numbers that end in "5" are 400MHz. You'll need to ensure your mobo is compatible with the correct speed.

HTH

[sego]

my R52 Board has the number 1860-W25 and came originally with Pentium M 750.
The M 735A definitely doesn´t work. Do you think the 725A could work ?

[fasterbybike]

my R52 Board has the number 1860-W25 and came originally with Pentium M 750.
The M 735A definitely doesn´t work. Do you think the 725A could work ?

Read my reply about the CPU numbering sequences. This info is available at http://processorfinder.intel.com

HTH

[underclocker]

Very strange, based on the R52 model info you provided, assuming you upgraded the BIOS and Embedded Controller, it seems that that CPU should work. The T43 model that it worked for me on used the same BIOS and EC. I'd ensure both the BIOS and EC are current, then I'd try it again.

If it doesn't work, I'd check the exact part number on the mobo. Perhaps it was swapped out for a different unit at some point in its life?