You can tell what a fuse looks like just by looking at the example pictures linked from the FAQ, and since all fuses look the same and are easy to spot on the PCB, you can just test them all.

I keep thinking that my display is slightly dimmer now than before I installed the lighting kit. I'm not certain, though, because it would only be a marginal difference if any, so I'm not sure if it's my imagination. But I think it really is a bit dimmer than when I got it.

And actually, I think it got dimmer only after I changed out the 3-LED pcb for a 4-LED pcb. So I, too, am wondering if I damaged anything.

So I am also curious what all the components are that might have an effect on the display brightness and how to test them. There are some in the FAQ, but I wonder if there are any more than those, because I've checked those and they all seem OK.