Peavey Vypyr 75 blown fuse

[Mick Bailey]

I have a late-model amp in right now with a blown F1.5A (230v model) mains fuse. The regulators are NJR and as far as I can tell the board has all of the factory fixes outlined in the 2008 tech note. I can't detect any other fault with this amp and with a replacement fuse it powers on and runs fine, with very little current draw - just a few mA, after a switch-on peak of 200mA.

These amps appear to suffer a disproportionate number of fuse failures. A search pullls up plenty of owners reporting problems. In part this is perhaps down to early models having defective 15v regulators. Maybe this one is a random failure.

Am I misisng something with this amp - a tech note or fix that I'm unaware of?

I don't want subsequent problems as the owner is relocating to overseas and won't be able to bring the amp back.

[Enzo]

Has the unit a history of blowing fuses? Or did it blow this one and none before. Was the fuse simply open, or was it blackened inside? If black, then some current surge took it, but if it just opened, well, fuses do sometimes just fail. Did the customer report the thing stopped working while in use? Or did he put it away one day after use, and then the next time he tried to use it, it was dead? Power up is the most likely time for a fuse to blow.

You can only do what you can do. It draws little on the bench, and has a small surge. You can crank it to see if it misbehaves at high output. But then what? Sometimes you just have to let it leave the nest.

The problem with internet reports is that it looks like a real problem when a bunch of people report some failure, but it ignores the tens of thousands of these amps that do not have the problem. How many times have I seen someone writing that "since my model (XYZ) seems to be a real problem model..." because he sees three or four threads on the model in a forum?

Blown fuses being one of the most common problems in anything, I have to be suspicious of claims that THIS model of something has a lot of problems with fuses blowing, when the insides of it are exactly the same as fifteen other models from the same manufacturer without the bad reputation for fuses. The unwashed masses tend to assume that when anything goes wrong, A. it has to have been caused by something bad, and B. that it must be some sort of systematic failure with the design.

When we repair something, especially if we find a specific problem causing the symptom, we then feel pretty confident it is fixed. But no technician worth his salt wil ever claim, "This amp will never fail again now."

You know what you are doing, trust yourself.

[Mick Bailey]

It's a power-up fault. No previous history of fuse-blowing and no blackening. The main problem with the model looks like it was fixed early on and picked up by Peavey shortly after the amp was introduced, but the tech note is dated 2008. My instinct is to put it down to random failure but I though I'd check here first.