I had a component in a sizable power supply open up, but I haven't had any luck identifying it. The PCB is marked with this symbol under the component: (two terminals, one on on each side)
I never saw this thing before it failed, but it looked exactly like a failed MOV after it failed (burnt up gray disk with leads flat on each side).
However, the component is wired in series with the AC line input, on the opposite AC line from a fuse. I've never seen any varistor used like this.
The power supply does not work with this component open, but I tried jumping across the two leads, and the power supply came right up, so it was clearly carrying current before.
So what is this?
Edit: Here is how it appears in the circuit: