Ampeg V4 internal fuse blown still working

Feb 11, 2013
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Hey everyone, I have a Magnavox era V4 that has a blown internal fuse but still turns on and functions fine. I was wondering if anyone has dealt with this before or if anyone with a v4 could post up pictures of the inside of their amp so I could check the fuse wiring. The external fuse is good and the standby light doesn't turn on.
Thanks
 
The power and standby lights can be problematic, if the amp is running fine the light probably isn't related.

I've read differing opinions on the internal/external fuses, some people say the internal is a backup for the external but I've also seen that it was added for the courtesy outlet. Either way, are you sure the fuse is blown? If it was shorted or bypassed that could explain things?

I don't have a picture of the fuse in my V4 handy but here's the wiring for my B25B with a similar internal/external setup. I soldered in the internal fuse as it was missing from the amp when I got it (you can see the tag noting that it should be a 6A fuse in there).

lOGXUWM.jpg
 
I'm positive the fuse is blown and I'm not sure if it's been bypassed or not but that would make total sense. I'll check the courtesy outlet later to see if it's getting power and put a new fuse in. Thanks for the info and picture I'm still new to these amps so any info is helpful!
 
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By definition a blown fuse is an open in the circuit, and any open in a circuit means no current flow. If the fuse is blown, and the amp works, it's absolutely being bypassed.
 
Just put a outlet tester on the convenience outlet and it showed power going to it. I'm going to have to open up the head again to see what's going on with the wiring. I'm certain the fuse is blown because I can see the break, starting to think it might be bypassed.