Marshall MG 50 DFX won't switch channels - Marshall Mg50dfx 50-Watt Combo Guitar Amplifier

SOURCE: Hi,I turned on my Marshall mg series 100 dfx and

I suspect the power supply for the effects processor has failed. The effects unit will "go crazy" when power supply is too low voltage.

If the amp has loud noise, then the power amp portion is PROBABLY OK.

I had a similar problem in a Behringer amp caused by a bad electrolytic filter cap.

SOURCE: Marshall MG50 DFX, the volume knob OD channel crackles

Either the control is damaged (happens if they get hit) or it is possible the circuit board it is mounted on has broken solder OR worse, a crack near the control. The unit will require servicing. Parts are readily available.

SOURCE: My Marshall MG 50 DFX has a noisy fan. Can I take

Bo, the fans cannot be lubricated. If the noise is from bearings, replacement is the only option.

SOURCE: Marshall MG100 MG DFX. Full speaker noise with all

well theres only 3 sections of the amp the problem can be in. Pre-amp, Power amp, or speaker. First Unhook the speaker. If you can turn on the amp after that and hear your guitar through the headphone jack this means your pre-amp is ok. at that point you can just take a voltmeter across the 2 terminals of the speaker to see if oyu have 4, 8, or 16 ohms. that'll prove the speakr is good. I'd also try to connect and disconnect the pedal a few times to see if the normals in the jack on the amp are just being stupid. if all this concludes no success, you sir have a power problem.