Sorry if this is in the wrong place.

Anyways, I own a Marshall MG100HDFX amp. It doesn't sound the best, but I've heard worse. Anyways, it sounds like it shorts or something.

I can crank the volume knob the whole way and then it just starts getting loud. Sometimes it makes a cracking noise and then suddenly gets very loud. Also, there is a very loud squeal when I first power it up. Does anyone know what's wrong? Maybe I need to re-solder the pickups or something? Idk, but if someone can give me any clue as to what's wrong with my amp and how I may fix it, that would be greatly appreciated.
Wires in your amp need soldering. They got loose because of the vibrations. Id say go to a technician, unless you know shit about the guts of the amp
i had the same with an old marshall of mine. spray some WD-40 down the volume pot.
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There are a tremendous number of things that could be wrong with the amp. It is impossible for anyone to diagnose it in a forum thread based on the explanation given unless by sheer luck it just happens to be a faulty pot or jack.

Bottom line is if you're able to rule out the couple of simple faults and afterwards still have the issue, it needs to go to a service center.