I have a T61 with a blown fuse F2 (underside of mobo, near the DC-jack).
There is what looks like a "7" stamped on it.
Anybody know what amperage this is?
I have a bunch of dead T23 and T43 mobos that could function as donor.

7 amp 24-volt fast burn. Littelfuse 429007

Try here:

http://www.newark.com/littelfuse/042900 ... dp/58K7915

did that ^ solve the problem ?

I think I just blew one of my T61 laptops using some crappy power supply that I bought the laptop with.

and where is the fuse at ? ... do I have to disassemble the whole laptop ?

That fuse is on the bottom of the mobo, underneath where the jack is, under some black plastic.
I replaced it, but it did not solve the problem.
I've given up for the time being.

thanks, took me some time to disassemble the whole thing only to find that the fuse is ok, lol.

in the mean time it looks like the laptop started to power up again ... bummer

I have a T60 motherboard which I think may be suffering from a blown F2 fuse, but I'm not quite sure if I'm checking it properly with my multimeter. When I put the probes on either side of C72, the circuit right next to F2, I get 20.2V. When I place it on either side of F2, including the solder points, I get no reading at all. Doesn't this suggest that no current at all is reaching the fuse?

The proper way to check a fuse is to remove all power from the system (AC adapter and main battery), then set the multimeter for the lowest OHMS (or continuity) range, then connect the leads to the ends of the fuse. You should get very close to 0 ohms for a good fuse; infinity (no reading) for an open fuse.

Disconnect all voltage sources from the board and set the meter to the lowest resistance (Ohms) range. Then probe with one probe on each end of the fuse and look for a Zero reading (good continuity) which indicates a Good Fuse.

Edit: rkawakami, You beat me to it. Great Minds think alike!!

I find Bridging the fuse with solder is useful if you are not sure if that is the problem. Yesterday my T61 died and after bridging the fuse it came back to life, thanks to this thread I know the value of that fuse so I can order a new one. I wouldn't recommend using the computer while the fuse is bridged though, just for testing.

Also, it is my understanding that you can not test components while they are still connected to the motherboard since the points may connect in another location. To properly test you'd need to remove the component from the mainboard, thats why I just bridged it... much easier and I'm lazy.

Not knowing WHY the fuse blew in the first place, you could easily damage further components by bridging it.
Better to piggyback solder another fuse over it!