Arcam AV8 turning off after initialising

Hi, I'm hoping someone might be able to give me an idea of a fault that has developed with AV8. When the processor finishes initialising there is a sudden loud bang through the speakers & the processor powers off. I took all other components out of the equation & just powered on AV8 & same thing happened minus loud bang as power amps were off. I'm presuming that it may be a power surge in the processor & it is powering off to protect itself. Frustrating thing is it was only fully serviced by Arcam 4 months ago & has hardly been used since then. Any opinion or advice greatly appreciated.