On my UPS, the buzzer looked similar to this one.

My UPS wasn't cramped inside once I took it completely apart. Although it was probably a completely different model than yours, so I have no idea how easy or hard it would be to work on yours.

The thing to remember about those UPS's, though, is that if you're taking them apart be real real careful not to shock yourself. The energy stored in the battery (and, I'm sure the capacitors), can be quite large.

Probably should have said something about that before encouraging you to open it up.