I purchased a Marshall Code 100H in April 2019.
It was replaced under warranty last week by the retailer as it had developed a constant electronic beeping sound.
I received the new head and right out the box it was much improved. I decided to get to grips with loading up my presets and patches so began by carrying out the latest firmware update as advised by Marshall, alas, the electronic beeping sound has returned.
It is constant and present with or without a guitar plugged in, elevates with master volume, cannot be fixed with a noise gate, the amp has been plugged in several different venues and the noise persists and it was not auidable before updating to firmware V1.44. Jul 2019.
Is there a means of rolling back the firmware or is there a known fix for this issue, it doesn't seem fair the retailer has to replace another amp which was fine until update was applied. Any advice would be much appreciated.