Marshall MG 100FX Amp Noise
I’ve had a Marshall MG 100FX for many years, and this problem has occurred regularly since the first day I used it. Sometimes when I turn on the amp it will begin making a loud, regular, popping noise that changes with the volume control and is consistent until I turn the amp off. I sometimes have to turn the amp on and off several times until it doesn’t make the noise. There doesn’t seem to be any rhyme or reason to when it does this. It either turns on and works fine or it turns on and immediately starts popping, whether my guitar is plugged in or not and on any channel. The “popping” is consistently paced, and my only decent theory was that I had a bad capacitor that would leak the noise every time it discharged, but I’ve had the board out of the head and I’ve tested all the capacitors and reflowed the solder joints on each one. I’ve been looking online for years and haven’t found anyone who has had the same problem. It’s been my White Whale of repairs so I figured I’d finally post it here.