Hey guys, i've stumbeled across a problem with my amp. I have a Peavey Vypyr 75W amp and i have never had more problems than a fuse that broke. I got the amp modded so i could replace the fuse from a holder instead of the shit that was placed by solder.

Anyhow, when i start my amp it turns on, but no lights from the leds are appearing. All i hear is a very quiet humming/buzzing noise and that's it. I checked the fuse and it was perfectly intact and when i start it my sanpera pedal are lighting up (but the pedal is broken so can't test the amp trough it)

Do anyone have any idea what i can be that i have to get fixed? The amp is working propperly overall and it's been taken care off since i got it so i've never had to do anything else exept the modding for the fuse so i could place it in a holder.

Thanks for answears! Will try to describe it better if there are anything that is unclear!
Did you check the solder joints of the fuse holder? It would effectively be like removing the fuse from the circuit if the solder joints are bad/broken.

Also check to see if any solder leaked on to other traces from the mod.
Does this amp have two fuses? When my Marshall DSL50W went it wasn't actually the mains fuse, but rather the TA fuse - which is a smaller fuse built to go before the main fuse
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Liaztraht yes i did and it seems to be whole.. also i got this amp modded för about 2 years ago now and when i checked the guy that did the job made it as perfect as possible
Anthony1991 i have no idea, i only found one fuse on my amp, but the fuse seemed to be whole but since i'm not sure i think i will have to change it.
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Anthony1991 i have no idea, i only found one fuse on my amp, but the fuse seemed to be whole but since i'm not sure i think i will have to change it.
if you have some extra insulated wire you can jump the fuse and see if it works. Or check with a multimeter.

I googled the amp and fuse blowing is common in them. Apparently there is an unwritten shut down order out there to prevent fuse blowing.
I worked on a Valvetronix amp that did the same thing. The amp would "turn on" to a degree- the speakers would produce just a bit of hiss or hum, but no guitar signal would pass and the main circuitry of the amp would not work. The problem was, you guessed it, an internal fuse other than the mains fuse.

Check the first fuse to see if that is the issue. You can use a multimeter if you have one, or you can pick up an LED continuity tester for cheap. If that fuse is fine, you will need to open up the amp and see if there is another fuse somewhere, and check that one as well.

Be careful though- do this with the amp off and unplugged. I do not think the filter capacitors in this amp will hold lethal charges, you can drain them to be safe, but if you are uncomfortable tinkering around with it please let an experienced amp tech handle it.
Last edited by Will Lane at Jul 18, 2016,
Sometimes fuses blow for a reason. Replacing the fuse itself then doesn't correct the issue. It sounds like the audio amplifier is working as you're getting hiss/noise out of the speaker. But there are several sub-supplies that are generated to feed the digital circuitry as well. There was likely a component that failed and during its breakdown caused your amp to draw too much current blowing the fuse. The fact that you don't bow fuses now indicates that the faulty component or circuitry is now "open". Your amp needs to be looked at by a tech.
Moving on.....