 Often when something mysteriously stops working, a blown fuse is to blame. Fuses protect devices from too much current, bravely sacrificing themselves to keep your electronics safe. Fortunately, they're inexpensive and easy to replace. You can tell when a glass fuse needs replacing by looking to see if the inner wire conductor is broken. But ceramic fuses are a bit more opaque. You can always use a multimeter's continuity test to check the fuse. Remove the fuse from its original circuit. Then set your multimeter to continuity, beep mode, and make sure it's working. Then connect one lead to each side of the fuse. If you don't hear a beep, that means the fuse is beeped, so you should replace it. But if you do hear a tone, then this fuse ain't blown. Yeah, this one's still good.