Hi all. I have a MA50h that will not switch channels. The LED’s on the amp change but the sound stays clean. ie: switch to OD channel lights change from green to red as it should but the sound remains clean. This also happens with the boost channel. Happens if I use the panel buttons or the footswitch.. everything appears to change channel but the sound. Channel led’s Change, buttons Change channel ,pedal changes Channels... but the sound stays clean Any ideas???