20 Most Recent Marshall Amplification Marshall MG15FX Guitar Combo Amplifier - 8 Inch, 15 Watts Questions & Answers

you may have a loose connection

Have you checked a different cable?. Also, when you plug in the unit, there should be a "pop" if everything is turned on. If there isn't, the connection is bad someplace.

Mixer uses balanced outputs, this unit does not... Also ground loops can be a problem. Make sure this and the mixer are BOTH powered from the same receptacle. The next problem is that the level of the mixer is MUCH too high for an amp designed to recieve guitar signals if you are sending a mixer into this. It is NOT clear how you are connecting this to a mixer... IF you happen to be trying to send signals from this to a mixer, either use a mic OR use a Direct Input box. You should tell us exactly how you are connecting this to the mixer since there are MANY ways, and most do not make sense.

check to see if your fuses are blown should be an easy fix

https://www.dropbox.com/s/6spu98r39t2wvcr/Marshall%20G30RCD%20Schematic.pdf

First check the preamp valve in that curcuit

Hi. Doesn't look like it as the speaker is a 4 ohm one and the head needs at least 8 ohm as far as I can see.

https://www.manualslib.com/manual/99237/Marshall-Amplification-Mg15msii.html

Make sure speaker cable works and is connected then check fuses. If it has a master volume, make sure it's turned up.

Most likely cause for this is an intermittent potentiometer. Check to see if any of them are mechanically loose as this is a sign that they have been damaged and could have cracked the wiper surface inside the pot causing this problem. Alternatively, any switch that controls any gain setting could also be intermittent or dirty. Gain of the amplifier should be stable, but is controlled by the feedback and signal injection at the pots so that is where to look first. Good luck, as intermittent problems are tricky, but sometimes better than no function at all which can be more costly.

What type of Marshall, please? First of all, control the fuse and let me know.

clean switch connections

Does anything happen while you turn the knobs on the amp? I had a similar problem with a yamaha amp. It turned out a couple of knobs went bad. Soldered new pots and it works fine for me now.

No, the ATV50 head is rated for 4 ohms total. Using both 4 ohm cabinets at once will fry your amp. Your only option would be to rewire your cabs internally to 16 ohms each by connecting the speakers in parallel, but that would cut your amp's power in half.