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Behringer GMX 212 Combo Amplifier Problem

Started by unowndanger, January 05, 2013, 06:06:26 PM

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unowndanger

Hello, I am new to the forum, so I apologize before hand if this is in the wrong forum. For the past year or so, my Behringer combo amplifier has been creating a lot of static and popping noises. I own around 5 guitars and quite a few guitar cables including 3 Monster cables and they all work fine on my other Roland MicroCube amplifier so I know the fault is with the Behringer. Is there any way to fix this static sound so that it is gone. I play on both distorted and clean and the static comes on both channels. It seems to come in at random times too, never consistent. The amp is on a carpeted floor, but I recenly put some scrap would to elevate it, but the static ic still there. It is also near an outlet and two power strips, but they are further away, I'd say about 6 feet away, from the amplifier and are usually turned off. Thank you for any help anyone can provide. This is the amp; http://www.musiciansfriend.com/amplifiers-effects/behringer-v-tone-gmx212-2x60-watt-stereo-guitar-combo

Roly

Welcome!


Dirty sockets and/or pots (contact cleaner or metho)

Conductive contamination of the circuit boards (e.g. spilled drink residue, wash, dry with metho)

A dry or broken solder joint (close inspection)

A failing semiconductor (serious electronics  ;) )


Does it show any physical sensitivity?  Wiggle guitar socket, move any control, thump case with fist?

Is it's character changed by any of the controls, vol, EQ, &c?  Or is it there the same all the time?

If the amp has an Fx loop Send and Return, try plugging a lead into Return and see if it changes at all.

HTH
If you say theory and practice don't agree you haven't applied enough theory.

Enzo

Turn the amp on, and let it sit there with NOTHING plugged into it.   Does it still make this moise, or does it only do it when something is plugged in?  And if so, does turning the guitar volume control to zero make any difference?

And agree to the thump test.  Ball up your fist and whack the top of hte amp.  Does that trigger the noise?  Or indeed does it make it stop?

And to rule out the electrical environment, take the amp somewhere else and plug it in.  SOmewhere not in your house.  Still does it?

J_Pooplava

Even though unowndanger hasn't responded, this is the same problem I am experiencing on my GMX, ongoing static and popping while playing. It is not the cable or the pots and the inside is clean. A thump on the top of the case stops it, for maybe 10 minutes. Bad board joints?

As an aside, I'd like to thank Enzo for helping me figure out the problem with my Peavey VT Classic 212 Phaser ICs while I was lurking.

Thanks all.

Enzo

If banging on it stops the noise, then it is a loose connection of some sort.  Open it up and start poking things with a wooden chopstick or other insulated thing.  Looking for anything that reacts and may need resoldering.

J_Pooplava

Quote from: Enzo on August 24, 2013, 12:39:26 PM
If banging on it stops the noise, then it is a loose connection of some sort.  Open it up and start poking things with a wooden chopstick or other insulated thing.  Looking for anything that reacts and may need resoldering.

Opened it up. Lots of miniature bits on those boards. Used the back end of a bamboo skewer to poke around. Hit one of the ribbon connectors and POP! The static stopped and the amp worked perfectly. Haven't pulled the board out yet for a closer inspection but hope a simple resolder will do the trick.

Would like to change out those crappy input jacks next if this works.

Thanks for the assistance.

Enzo

Sometimes the pins on a ribbon cable get a little dirty, and all it needs is to pull it off and push it back on.  You may have actually fixed it.  I would not pull the boards and resolder anything unless it starts doing it again.


Likewise the input jacks, unless they are not working well, leave them alone.


I like to say, when an amp works, stop fixing it.