During the last wash, I got water into one of the two amps for my empeg. I opened the case after it kept blowing the external 30A fuse. I found two parts to be shorted which look like voltage regulators (but I don't know what they are). They are three-legged parts with a plastic body, with a hole on the metal back that extends over the body (I can attach pics, if necessary). There is a whole bunch of these in my amp, so it was easy to find out, which ones were faulty by measuring resistance across the pins. I removed the ones that had zero resistance across the two outer pins.
The three lines of characters on the plastic bodies of the two parts read as follows:

IRF 540
I<unrecogn. char>R 115E
30 18

What part is that? I do have some voltage regulators lying around here from Patrick's tuner kits (had to replace some there, because of a power supply that was set too high), but the text on them doesn't match.

Thanks for any help!