HH Studio 50 guitar amp - needs some fixing (Kemptown BN2)

This guitar amp dates back to the late 70s/early 80s. It switches on fine but it cuts on and off when in use. It may well be any easy fix for someone who has the skills. It’s a bit too heavy for me to get to a repair shop these days (or to a gig), which is why I’m Freegling it. It comes complete with power cable and protective soft cover for when in transit. It’s a well regarded model of amp and I hope someone can get some joy from it. Beer bottle in photo to give scale!