Just have the technician who gave you the estimate replace the power supply. If you are looking for a Sansui power supply to drop in, lotsa luck unless you come across a salvage one. Even if you were to score one, you would need a schematic unless you are familiar with power supplies and precautions you should be taking. Buying vintage pieces and paying to restore them, go hand in hand. I have had a number of vintage Marantz pieces restored ... replacing the power supply is usually part of the equation.
Regards, Rich
Regards, Rich