it's not sophisticated phonostage and can be easily fixed by local tech. if you open the box, and touch tops of the DC caps and hear buzz or more loud wind, than probably you've ID'd some of the bad ones that need replacement.
after all these years of usage the solder joints need to be reapplied fresh as well. the best way is to remove old solder and reapply with new and shiny one. give your wiz these tips and he'll probably helps you to fix this unit. as to temporary stop, it even more proves my thoughts.
to be even more precise and without going into too much details simply replace ALL DC caps and reapply solder.
after all these years of usage the solder joints need to be reapplied fresh as well. the best way is to remove old solder and reapply with new and shiny one. give your wiz these tips and he'll probably helps you to fix this unit. as to temporary stop, it even more proves my thoughts.
to be even more precise and without going into too much details simply replace ALL DC caps and reapply solder.