That's not the fan, that's the fan's power supply circuit. If you have one of those loud Tivos and you want it quieter, you'll have to take it apart and come up with a different power source for that fan. Or carefully put a large capacitor in parallel with its power leads. There are other threads about how to replace the fan (even though the fan itself isn't really the problem), which also contain ideas on how to do those things. This thread is for people who have quiet Tivos (or who have already made them quiet) and are looking for a little extra cooling capacity.