20 Most Recent Marshall Amplification Marshall MG30FX Guitar Combo Amplifier (30 Watts, 1x10 in.) Questions & Answers

Hi J Wade. I'm Dave P. I'm not a guitar amp expert or technician but I've been using amps and effects for 35 years and there are a couple things I can suggest.That kind of periodic noise/switch noise can be a symptom of having the polarity of the amp reversed. If your amp has a 3-position OFF/ground switch, try reversing the ground. If it doesn't, take the plug and turn it around. Just don't get near a microphone unless you're sure your amp is grounded the same as the P.A. It could fry your lips off.Dirty switches to that too. You said the noise is in time with the delay's tap time which is set by a foot switch. If tapping that switch the first time generates a pop, the delay may have catch it and is repeating it. Turn off the amp, remove the delay foot switch and turn it back on. Still noisy? If not, give the foot switch a good cleaning.When you turn the EFFECTS knob up, is it scratchy? Might need the potentiometer cleaned. What happens when you specifically turn the DELAY level down all the way while using the other effects? Noise still there?That's all I've got. Hopefully, it was helpful. Don't wrack your brain over this too much. There could very well be an internal problem with your amp that will require a trip to the shop. You don't want to open it up yourself. Rock on but be safe.Dave P.

try another speaker or test the speakers on another amp. if the speakers are working then it's your amp . check out the output ic's. they maybe blown.

Often the boards will be the same, but the power transformer MAY have higher voltage. Also you have to be careful as the speaker might NOT take more power. If you need more power, get a bigger amp. A lot of the smaller amps use the TDA2050 chip which can generate a max of 32 Watts RMS. The bigger Marshall's 50DFX use the TDA7293 or a pair of them which is a different animal entirely.

Exercise your warranty IMMEDIATELY since you just bought it! If you bought this used, you LIKELY bought someone else's problem. The problem is likely in the digital effects area... probably a bad cable contact... but if under warranty DO NOT mess with it... return it for replacement or repair.

Likely either a rectifier diode, a filter capacitor, or the power amp transistor or chip/stick have shorted and failed. Unless you are electronically adept, it is time to take it to the shop as the cause of the failure will not fix itself. DO NOT replace the fuse as additional damage may occur..

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.

No, the ATV50 head is rated for 4 ohms total. Using both 4 ohm cabinets at once will fry your amp.