gnome@oliveb.UUCP (Gary Traveis) (07/15/86)
> > In article <3937@decwrl.DEC.COM> white@euclid.dec.com (Robert White) writes: > > > >In a recent posting, it was stated that when varistors have seen one > >too many surges, they explode. In my experience, varistors explode > >only when drastically overstressed. The more typical failure mode > >is that they quietly become an open. Evidently, not always. I just had my pinball machine (FLASH) go down because of a blown fuse. Since I wasn't sure if the fuse blew from fatigue, I replaced the fuse and tried to power-up. As it turns out, the fault was easy to find because the MOV inside the unit promptly self destructed by catching fire and sending a small plume of smoke up to the ceiling. Luckily for me, I powered it up by way of plugging it (cautiously) into an extension cord and when I heard the plug go POP I imediately stopped trying to insert the plug any further. The new fuse did not blow (in the time I had it powered) but the MOV is cracked-open and burned. It is still in a low resistance state. I'm glad that Williams had the foresight to mount these puppies in a "blast-safe area" that is framed-in by metal plates and a Corcom line filter. I'd hate to think of one of these failures in a plastic box! Gary (hplabs,allegra,ihnp4)oliveb!oliven!gnome