Turn the printer on, heat up the bed and hot end to a random temperature, wiggle and bend wires around. This will check to see if there is a short in the wiring, which will cause a abrupt shutdown. If the print shuts down when you bend for example the bed wiring, focus on sections of the wiring. This will verify where there is a short or break. Replace the wire(s) if necessary.

If you don't find anything, next thing to check is the control box wiring. Leave the control box unplugged and switched on for an hour, this will make sure there is no stored electricity in the power supply. Remove the bottom panel, it is held in with M3 screws. You will see the power supply. There should be a terminal block on the power supply towards the rear of the control box. The terminals will have a clear plastic cover the screw terminals, it can be flipped up to expose them. Wiggle the wires to verify none of them move, tighten any terminals that are loose (not too tight or you will strip the Philips head).

Up next is the control board wiring, it is under the power supply. Remove the power supply by removing the four Allen screws in the side of the control box. Try to keep one hand on the power supply when removing the last screw so it doesn't suddenly fall into the control board. There should be enough slack in the wiring to lay the power supply on top of the control box. Now you'll need the main board, there will be more screw terminals. Wiggle all the wires to verify none are loose, tighten if necessary (again, not too tight).

There is a MOSFET that controls the heated bed that is located in the rear of the control box, it has a heatsink on it. There are more screw terminals here, repeat the steps above. Ideally there should be no loose terminals anywhere, if you found any that was most likely the cause of your problem. If you happen to find all terminals are tight and proper, the power supply is failing and needs replacing. Tinymachines has a replacement CR10 power supply but it's currently out of stock. I found the same model on Mouser for $42. Jungle website link