T40 Motherboard Repair

[megascribe]

I bought the T40 on Ebay about five years ago. It was in good shape and didn't give me any problems until I started messing with it - first a memory upgrade to one gig, then a bigger hard drive. Then I did something stupid, I upgraded the CPU and tried to clock it using the wire trick. That's when the lights went out. It seems the wire fell into one of the CPU socket holes shorting out the CPU. Anyone know the best way to get the wire out? I was thinking of cutting a slot on the motherboard under the CPU socket between the contacts with a dremal to remove the offending wire. If I go ahead with this fix would I be cutting into any unseen contacts under the CPU socket? I don't see any solder points under the motherboard that cross over the bottom of CPU socket. Has anyone out there ever have this problem?

[Harryc]

What was the wire made out of? Steel? Use a magnet.

[RealBlackStuff]

I could send you a non-working T40 mobo (only because the security-chip is missing) for $10.- incl. shipping, so you can 'practice' on that, and see if there are any 'hidden' contacts or whatever underneath.
You could also try and pry the top layer of the CPU socket off, to see if that would help.
I have 3 to choose from:
P/N 91P7992 FRU 91P7993 or
P/N 91P7997 FRU 91P7998 or
P/N 91P7715 FRU 91P7716.
PM me if interested.

[poshgeordie]

Sorry to hear of your problem.

Please don't cut a hole in the underside of the board because I believe it's multilayered, ie there are a number of layers with tracks in each layer, and you may cut through one / some of those tracks.

Am I correct in understanding that there is a tiny bit of wire which has fallen down one of the holes in the top of the CPU holder and you know which one it is and you can't get it out?
Silly question but have you tried turning the board upside down and giving it a bit of a tap on the underside - be careful though that you don't loosen the graphics ship soldering and give yourself that fault as well.

Or is the wire somehow between the bottom of the CPU holder and the top of the motherboard and you need somehow to get it out?

I'll think about both of them and get back if I can think of anything.

@Harry - let's hope it is steel but more likely to be copper...

[katar83]

You can take off the white layer of the CPU socket and then put it back but I dont think its a CPU socket shorting something there.

[megascribe]

Thanks for the input. Sad to say it, but no, it's fine copper wire. There's no way to shake it loose because the pin holes of the CPU socket are too small. The only way I can think of is to remove the socket or cut a small hole under it to suck out the wire. It's very small and hard to handle.

[poshgeordie]

Sorry I still don't quite understand where the piece of wire is.

Either - has it fallen down one of the tiny holes which the CPU pins fit into in the CPU socket - ie from above.

Or - is a tiny bit of wire between the bottom of the CPU socket and the top of the motherboard and the wire's stuck underneath.

If it's the first one, you could try removing the sliding part of the socket, turning the board upside down and then use some sort of suction device like a solder sucker and see if it can be sucked out of the hole.
Alternatively a small tube over the hole and sucking hard on it may work but be careful not to swallow the wire if it comes out!

If it's the second choice short of desoldering the CPU holder, I don't have any other idea. Note that the holder is soldered to the board with a ball grid array (BGA) like the graphics chip so this is not really possible without the right equipment.

Drilling a small hold from under the board is as I've said previously a bad idea since you won't know what tracks you're drilling through as you go through the board layers.