How many times have you had to work on a piece of electronic equipment that has quit working, only to find that it is, or was, a blown fuse? The piece of equipment seems to work after you replace the fuse, but do you ever ask yourself, what caused the fuse to blow in the first place? It's possible the fuse may have just been getting old, with a lot of heavier than normal current flow through it over the years and the link inside may have just deteriorated over a that period of time. On the other hand the fuse may have blown due to a sudden high spike of current, such as from a lightning strike, and done its job to protect the electronic equipment and prevent a possible fire. Before you just replace the blown fuse with a good one, look over the piece of equipment for any obvious evidence as to why he fuse may have blown. If there is no obvious problems try a new fuse. If the new fuse blows again, then there's a bigger problem that may take a while to fix. If the new fuse does not blow, then you may have been lucky. But just because the new fuse didn't blow right away doesn't mean that you have fixed the problem. The new fuse may not blow for some time, indicating there is a growing problem in the piece of equipment that will have to be found before it causes major damage to the equipment, and cause it to fail right when you need it the most.
(Reprint, with modification of, ARES Zone 3 Bulletin NR 00.40)
Ken Harris WA8LLM
Wood County WV;
ARES Assistant Section Coordinator WV
ARES District Emergency Coordinator WV DISTRICT 3