@livingwellinco , I have not had this particular model, but have owned a number of the VTL amps.
The main power supply filter caps over the years get cooked by the heat from the tubes and transformers. Even if the caps test good, would still suggest replacing them with 105C rated parts of the same capacitance. Also you may want to ask your tech to re-solder or re-flow all the octal tube sockets solder points to the board. Over years of heating/cooling cycles, its not uncommon to see some cracked solder joints.