I have a Marshall Code 50. Not sure what’s happened but when I plug my guitar into it, I get no sound and the presets are now being controlled by the guitar volume knob. If guitar volume is full high, display on the Code quickly scrolls thru presets. If guitar volume is full low, you can individually scroll thru presets by quickly turning volume knob up then quickly back down. No volume from cabinet regardless of preset volume or master volume, only static. Have tried with both electrics I have and both cables, in various configurations with no difference.

Any help is greatly appreciated.

Thanks. Kevin.