Haven't spent too much time looking closely at T4x motherboards but this is what some of the fuses in a T23 look like:
(highlighted in blue boxes)
(at the middle-top of the picture, to the left of the label F2)
Fuses generally are labeled with "F" numbers. Finding them is a matter of scanning around the motherboard. Figuring out what they are (the current rating) can be easy in the case of the white ceramic fuse with the silver endcaps (it has 10A on it; 10 amps) or next to impossible (like the F2 fuse which has an "FU" code on it). Also, it's been my experience that the fuse is one of the last
things to blow out when there's a short or power problem.
To answer your other questions in the other post I just locked... I don't know of any photos/scans which detail the exact locations of all of the fuses on a T41 motherboard. Maybe somebody will post that information. Replacing them requires a fine-tipped soldering iron, a steady hand, tweezers or needle-nosed pliers, good eyes and a bit of luck. Surface mount components are not as easy to work on like "through hole" parts since most of the area which is attached to the motherboard is resting on the surface of the board. That makes getting them off and on the motherboard a bit harder.
Once you locate them, you can test them with an ohmmeter. Zero ohms (or very near zero) indicates that the fuse is still intact; anything other than that is an "open" and means the fuse is gone. Recently Merlin Witt
posted a warning about checking some of the very low current fuses using a multimeter. Apparently it is possible to blow the fuse simply by trying to check them:
ref: http://forum.thinkpads.com/viewtopic.ph ... 438#402438
I haven't run into that problem yet, but then again I don't know how much current my meter is providing when it is in the lowest resistance range.
Also, here's a recent thread about T42 fuses: