If you’re trying to determine whether or not a particular M type fuse has blown, the best way to do so is by testing it with an ohmmeter. To begin, disconnect any power source from the appliance or device containing the fuse, and remove the fuse from its holder. Once removed, use your ohmmeter to test for continuity between both ends of the fuse – if there is no continuity (or resistance), then this indicates that the fuse has blown. It may also be possible to tell visually if a fuse has blown; they are usually designed with a small glass window which will show when silver strands inside have melted due to an overload in current. If you can see that these strands have broken apart, it means that your M type fuse has definitely been compromised and should be replaced as soon as possible!