Marshall MG100fx hissing like crazy

[The Dude]

Puzzling here too.
Would NEVER have imagined to find that inside a Marshall labelled head.
Not surprised on, say, Line 6 stuff, or even a few "Vox" ones ... because we all know they really are Korg made, the kings of digital keyboards and pedalboards, but ..... a Marshall??? (

I can't help but wonder what a certain "member" would have to say about this. His beloved Marshalls made in Japan.............Or, maybe China is crap but Japan is OK?

[BowerR64]

I have one of these its Red im not sure what model it is the MG100FX, it has the little splatter graphics around the power button. Also the power button is round not rectangle like the last generation. Everything ive read says this is the MG4 series but im thinking the graphite looking MGs are the MG4 series? Not sure but i sure like how this version of MGs sounds, i have 3 of the last generation that has the rectangle toggle the MG30DFX and 2 of the MG10CD and these newer ones sound MUCH MUCH better. The tone isnt as scooped and its not as fizzy sounding as the previous ones.

When i got mine it had no sound either after playing around with it and pushing on the master and volume controls as i turned them i started getting sound. I decided the master volume was bad. After i tore it apart i noticed all the pots on the front pannel are all the same volume. I decided of all the controls i could live without reverb so i swapped it with the master and whala! it worked. I then noticed that others were bad.

If you change any setting on any of the 4 channels after you save them that channel LED will blink, so i could save a setting then slowly rotate the other random controls till it started blinking. 5 of the 9 pots on the front panel i wound up replacing.

After replacing them i tore the pots apart and all of them had little spots ground into the traces on th elittle board inside the pot. Just from turning them back and forth it eats away the carbon on the pot board and soon eats it away. All the pots on this mode are really cheap. I try and avoid turning them as little as i have to.

I got it not working off craigslist for $50. so it was worth it for me to invest in some pots. I think the pots were like $6-7 each on a site called vintage amp parts or something like that. They had them on e-bay also

I hope this helps some one, its not a bad sounding amp if you can get it cheap enough.

[gui_tarzan]

I fixed one of these last year that had a bad hiss and would cut out randomly. Our singer bought it from me and it has been working great ever since (knock on wood). All I did was touch up a bunch of solder joints that were iffy.