T20 Motherboard Swap - CPU Compatability

[Fisherman]

I have a T20 (2647-T1U)that has a bad motherboard. The CMOS battery is good (3+ volts); Good battery and power brick. The HMS says my motherboard (700mhz) part number is:12P3360. The new motherboard I have coming is part number 26P8098.

Can someone tell me:

Will my existing CPU (7025A144 SL3Z8) and memory (128mb synch 100mhz cl2) work in the board I have ordered?

Also, does anyone know where the solidstate? power on relay is located on the motherboard? On my board there is a part labeled 1R0MH H04 just southwest of the keyboard connector. It has a few turns of copper wire and looks like it might be the culprit.

Any help or advice would be apprecuated.

(1st. post)

[losmeme]

Hi;

Looks like you have ordered a T22 board for your T20. Yes, it should work without problem as the T20-T22 used basically the same motherboard. Go ahead and switch out that memory and CPU!

I just purchased a T20 (2647-86U), a 700MHz just like yours, and was successful in upgrading the CPU to 1GHz following procedures outlined in the HMM. Worked like a charm and took less than 30 minutes.

A new 1GHz CPU, a full 512MB of RAM and a new, 5400 RPM hard drive were great upgrades to this machine, and showed a nice little performance increase.

Good luck with your upgrade.

[Fisherman]

Thanks for the response.

Do you happen save the number on the 1Ghz CPU? I'm thinking of doing the same after I do the swap.

After a lot or reading here I'm still not sure about the SLxxx number on the CPU. I just want to hear from someone who has done the upgrade to the 26P8098 Motherboard.

[tfflivemb2]

The CPUs are interchangeable between the T20, T21 and T22, as long as the T20 was originally 700Mhz or better. There were some low end T20's with a sub 700Mhz cpu. These seem to be a different animal.

[losmeme]

I used an SL53S 1GHz Intel Pentium III Mobile CPU purchased off eBay. I had seen the S-number in a post on this forum, and found that exact part no prob on eBay.

At the same time, I also purchased a new T22 Heatsink Fan, which has a wider heatpipe on it. This was only $10 delivered, and it was a brand new heatsink/fan. Your old one will work, but it won't dissapate the heat as well as the newer one, meaning you'll have to suffer a hotter laptop with an upgraded CPU. It is a cheap upgrade, and more than worth the cost IMO.

The only thing unexpected that I ran into concerned the new heatsink. It is a little wider than the old, and I do remember a post here that mentioned small plastic parts having to be trimmed off the case bottom. I thought that meant the hard plastic bottom of the laptop.

What needed trimming in the end was a flimsy piece of plastic I think is called the spill channel. You have to pull it out to fully access the CPU. (it isn't really attached to anything, it just sort of lays there, underneath the keyboard.) A few swipes with an Xacto blade and it fit back in like a charm.

After everything was re-assembled, the laptop booted up no problem. I did immediately enter the BIOs setup on that first re-start to re-enter date and time and to set default config. (CPU Upgrade procedure calls for removal of CMOS battery.)

I noticed that the BIOs correctly identified the CPU as a 1 GHz. After logging into Windows, though, both CPU-Z and ThinkPad Configuration seemed to be under the impression that I still had a 700MHz CPU. Apps launched funny, the machine was sluggish. I turned off the SpeedStep utility, restarted, and BadaBing! The new CPU was recognized, and I finally felt the performance increase.

The T20 is only my second laptop, (A ThinkPad 240X was my first) It isn't difficult to see after this upgrade why ThinkPads are so popular. I won't be looking at another brand, ever, after this very positive upgrade experience. Geez, if only ALL technology were this easy!

[Fisherman]

Many thanks for the information. My new motherboard should arrive over the next 5 days. After I do the swap, I'll post the results here if you're interested.

I still want to investigate exactly what went wrong on the old motherboard. I still suspect the component mentioned in my first post is the only thing wrong with the old board.

There must be a lot of people with dead boards that would be interested in a repair procedure.

[RoxyRose]

Hi,
This is a great thread. Learned lots of info from it.

[Fisherman]

First of all Thanks you for the responses and follow-ups to my posts. There is no way I would have been able to repair my t20 without this forum group.
THANK YOU THINKPADS.COM.

Summary:
Consulted Motherboards.com - 3 hours
Searched and bought EBAY for motherboard - 1 hour $50.00
Joined Thinkpads.com and asked some questions -1 hour
Used answers from Thinkpad.com members and HMM
to replace motherboard in laptop. -4 hours

Powered up fixed thonkpad. PRICELESS!!

Details:
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Well here my results; I hope they can help someone else.

Symptom: Power button pressed and no power on. Only the Disk drive light blinked once and the battery charge light came on and remained on.

1. Confirmed that my thinkpad motherboard by removing the battery and removing the CMOS battery bracket underneath (1 screw). Leaving the CMOS battery connected I took a voltage reading (sharp points on meter probes) through the yellow shrink wrap. Voltage was 3.23v. Well within HMM specs.

2. Searched EBAY using T20 Motherboard as a search arg. I found a board PN. 12P3923 (no CPU) that said it would fit the T20,T21,T22 models and was compatable with the following FRUs: 08K3381, 12P3890, 12P3923, and 26P8098 . Bought it.
3. Downloaded HMM for my system and followed steps to remove the bad board. Moved the 700 Mhz CPU to the new board

Just a note here.
You need a good set of small philips screwdrivers here. The old radio shack blue plastic case with a clear lid variety worked great. I also noticed that while there seem to be a lot of screws in the T20 it's not so bad. There seem to be only three types, and each type has its own length. So mixing them up was not a problem. To keep me from mising them up, I used a piece of masking tape to tape any screws removed with a part to that part. This made it easy to re-assemble the machine a week later when the motherboard arrived.

4. Assembled, prayed, and powered up the system. Used F1 to enter the setup program. Loaded the BIOS defaults and set the date/time. Pressed Save and EXIT.

5. Booted with the hard drive (Windows 2000). Had to select boot normal on first boot. Let the run a NTFS drive check. When W2K finished booting, my display mode was now 16 colors and 640x480. I right clicked the desktop and selected Properties to get to the device driver tab. Here I selected upgrade the driver and pointed to the C:\windows\system(32) to use the already installed drivers. This fixed the display resolution back to normal.


I then upgraded to Windows XP Pro, but that's another thread. If anyone is interested in that, let me know and I will post.

My next project is to try and repair the bad board. I will post my results on that if anyone is interested.

Thank you to losmeme and tfflivemb2 for your help.

[tfflivemb2]

Glad to hear that you got it working!!

[losmeme]

Aren't ThinkPads the greatest? Congrats on fixing the machine, knew you could do it!