R52 1858-CTO Processor Problem

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90base · #1 Post by **90base** » Mon May 05, 2008 11:48 am

I have a Thinkpad R52 1858-CTO it has the Celeron 1.4 in it with the processor model number of SL68K. I recently bought a processor off of a fellow member on here which is a Pentium 1.5 with the model number of SL6F9. I was told on here by a few people that it would work. I put the processor in and the computer turns on but the screen never comes on. The LED's indicator lights on the bottom of the LCD light up, I can hear the hard drive spin up but still no video. Is it because the processor is incompatible with my system?

Thanks
Brandon

#2 Post by **Kyocera** » Mon May 05, 2008 12:04 pm

Can you hook up to an external monitor to see if anything else is happening video wise?

djpharoah · #3 Post by **djpharoah** » Mon May 05, 2008 12:47 pm

Also try putting the celeron back in and flashing it with the latest bios? My T41p didnt recognize its new 1.7GHz Dothan at first but did after a bios update.

90base · #4 Post by **90base** » Tue May 06, 2008 11:22 am

I dont think its a vid. problem as it works just fine when I put the Celeron back in it. Also the bios and embedded controller are updated to thenewest release.

#5 Post by **Kyocera** » Tue May 06, 2008 12:03 pm

I dont think its a vid. problem

I don't think so either, I was thinking you could see where you get in the boot process (possibly) when connected externally.

#6 Post by **Harryc** » Tue May 06, 2008 12:11 pm

That CPU (SL6F9) is a Pentium M Banias 400Mhz FSB. The R52 takes a 533Mhz FSB Dothan CPU. A Pentium M 730 at 1.6Ghz would be the right low end CPU. It runs PC2-4200 RAM at 533Mhz as well.
http://en.wikipedia.org/wiki/List_of_In ... processors

The only caveat to the above is the fact that I have never upgraded from a Celeron in an R52. That is a point to ponder ... I'd look at socket, voltage, BIOS, and chipset compatibility. If those points are the same on your board as on a Dothan based R52 then you should be good to go.

#7 Post by **underclocker** » Tue May 06, 2008 12:28 pm

An R52 with a Celeron CPU probably used the motherboard variant with the 910GML versus 915GM Intel chipset. This, plus the support that IBM coded to the BIOS and EC, probably means that only Dothan-based CPU's will work for you. From experience, I am sure they can be either 400MHz or 533MHz bus CPU's, but I can also tell you that you can not go too fast. A 1.6GHz Dothan 400MHz bus CPU worked fine for me, on more than one occasion. But the same machines had trouble with 533MHz bus 1.86 & 2.0GHz cpu's.

Intel officially only supports Celeron CPU's on 910GML chipset motherboards, but as I said, the slower Dothans run just fine. I'd stick to 1.73GHz or less.

On the other hand, if you happen to have a 915GM based motherboard, you can very likely upgrade to 2.26GHz without an issue.

I think your mistake was using a Banias based Pentium M.

Good luck and please report back your results.

#8 Post by **Harryc** » Tue May 06, 2008 1:55 pm

I'm glad I mentioned the caveat, because I figured there was more to this than meets the eye. Nice explanation Ed.

#9 Post by **Kyocera** » Tue May 06, 2008 2:59 pm

Ed knows his stuff, I upgraded my R52 from celeron to Pentium from a processor I bought from Ed. That was a pretty easy swap, so I was thinking this gentlemen should really have no problem.
Mine was an 1858- (forgot the rest) too.

R52 1858-CTO Processor Problem

R52 1858-CTO Processor Problem

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