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 !