how to correct master volume bleed through in a Marshall mg10

[steve]

I have recently purchased a marshall mg10 . When the overdrive channel is engaged as you increase the gain for a long singing distortion the volume increases and the master will not lower it to a desireable level. What can be done to correct this ?

[THChrist]

i dont get it. you  have 2 volumes, one for each channel, there's no master volume per se. you should be able to dial gain at 10, and the overdrive volume at 3 o something like that. i have 2 Mg15 (CDR and DFX) and it's almost the same (except for the FX and EQ). Have you read the manual? maybe your amp is damaged.