It is a very common issue with these power supplies. All the electro caps go faulty. Especially the little ones on the small boards. You need to change them all for 105 degree rated caps. The old 85 degree caps dry out. Also do the caps in the regulator PCB - its separate to the power supply. You may also see the odd tantalum cap smoke, bang or go faulty in the rest of it. Takes allot of time to replace them all but well worth it. The very best general purpose analogue test gear ever made.
Chris, ZL1CVD