Marshall VS100 combo - occassional overpowering buzz

[busydoingnothing]

I've had this problem for a while and I have a decent workaround, but now I'm playing in a band and we're going to start playing shows and I really need to fix this. When I'm playing, the amp will sometimes just start buzzing loudly, and you can't really hear the guitar over it (or hear the guitar at all). It sounds almost like what it would sound like if you plug in a cord and hold the tip of the other end.

To work around it, I found that if I pull the guitar cord down and wrap it down under the "leg," thus creating tension, I won't have this problem. Is it simply a bad input jack that needs to be replaced, or potentially something else happening?

I'm a novice when it comes to electronics in this manner. I've been able to fix a cold joint on one of the caps in the past without a problem, but when it comes to reading schematics, I'm rather clueless.

Thanks in advance!

[Phostenix]

If you just push down on the plug of your guitar cable at the input of the amp, does that also make the noise go away? Have you tried other cables?

[Rayme]

Sounds like you could be dealing with a loose grounding issue and a quick look at the jack could reveal a simple fix.

[busydoingnothing]

Phostenix: I've tried multiple cables; same result with every cable.

Rayme: What would I be looking for? A bad soldering joint?

[Rayme]

If the jack is not loose, than there is likely a loose wire on the jack. Just a touch of solder is all it needs. Jack may need cleaned which I use a small bore brush(brass) from a gun cleaning kit and run it thru the inside of jack. Works great.

[Rayme]

Just realized your jack is soldered to a circuit board but could still be a loose connection. These jacks take a beating. Make sure jack is tight in chassis.

[Enzo]

Yes, resolder that input jack to the board. if teh copper traces are too damaged, then we have to patch them with wire.

[Lee_ranaldo]

It might be just a bad solder..

if u're not skilled with electronics ask some friend that is to help u out

Always fix the solder joints on the jacks mounted on the main PCB (the board that has all the componentes)

Never do this with the amp PLUGGED into the wall socket

If the amp is older than 10 years or ahve been used and abused too much i'll suggest changing all the electrolitic caps..

Stick around here so u will learn some more how to obtain the best tone of that amp.

Be careful and Good Luck!

[busydoingnothing]

Thanks for the advice, guys. I'm going to take the amp apart this week or this weekend again and double-check the solder, or maybe just resolder the jack to the board regardless.