How can you tell if you have a bad motherboard?

1st of all I would find another computer shop because they should have been able to tell you what was good on the "parts" t40. They should have been able to say if it was power, memory, mobo, or hard drive. 2nd its not that hard to change the mobo but just make sure you get the static electricity out of you before you begin. Good Luck

you can look here for the beep codes: but I didn't see 4 sets of 4. I'm all in favor of swapping dead for dead to make sure. Isn't a dead board what made the person sell your "parts" computer though?

You might be best off practicing by swapping the two (probably) dead ones. If you go slow and look for help online (repair4laptop is good) you'll probably be able to do it fine. Get a very lightly magnetized screw driver a credit card or other flat piece of heavy plastic for popping open catches and the like and get a digital camera to take pictures of difficult parts. Hey, if you don't get it to work, when you go to replace it with the new one you buy, you'll have experience.

good luck

well I wrote a long reply but lost it when the session timed out. So I'll make this one short

Check the power jack on the "Parts" laptop to make sure that isn't the problem. Check it for both dead motherboards. If the parts computer was stripped, it most likely has a dead motherboard. Stripped computers are either sold for the motherboard or the screen with the other one being the problem. You bought it for the screen, so . . .

once you have it out, you might as well look at it for visible damage, unlikely that you'll find any. Then plug it in and check voltage with a volt meter. look for the first solder point downstream from where the power jack connects. If you test anything else, you might blow a perfectly good board.

It isn't too difficult to remove a board. Be careful with ribbon and wires connected to it. Remove ribbons by releasing the receptacle (there are several kinds) and remove wires by using needle nose pliers to pull on the MALE plug end NOT the wire NOR the FEMALE receptacle.

To pop apart clips, use a credit card or "spudger" which is a hard piece of plastic used to slide between the pieces and apply controlled pressure.

keep track of where all screws came from and either mark the different sizes with a dot from a marker (if you have different colors of markers it works great for marking exactly what size).

When pulling the board out, if you get any resistance look for more screws to remove.

PM me if you need more specifics, but I'm sure with patience you can do a great job without braking anything important.

4 beeps on Thinkpads _MIGHT_ be bad memory, if you can, try first replacing only the memories, if symptoms keep coming, then definetly it might be mobo issues. As of the replacing yourself the motherboard, you can slowly do it, grab a few stickers for the screws (to left them glued on the sticker in correct positions) i take about 15 minutes to replace a motherboard on T4* series and a user that is not used to do it, calmly doing it should take about an hour or so.

*try not using Kingston memories as Thinkpad's tend to have a few bumps with those memories occasionally