The shutdown problem is definitely the power supply. It has a problem
with being mechanically intermittent. If you tap the power supply it
will shut down. I sent my power supply out for repair at a module
repair company. It came back with same problem, they went over it
again and it still had shutdown issues when tapped. They sent me
another power supply they had in stock and it had the same shutdown
issue. I wasn't sure if it was the power supply any longer. I took a
look at the power supply and was able to repair it myself. The repair
is soldering all the tabs holding the heatsink on the power supply to
the board. The connections don't look bad but they are. I also
soldered the transistors mounted to the board / heatsink too. Good
Luck !