The Well Audio Said
You could measure the voltage on C108 with a DMM (positive leg), you should measure around 13V.
If there is 0V you could measure the voltage on the two terminals of R7 versus ground to understand if there is a shutdown condition due to current overload.
You should measure around 0V on both terminals, otherwise current overload condition occur.
Finally you could check R40 and R41, they are protection resistors which burn in case of persisting short circuit.
C108 has 13.5 V when the Power switch of the power board is on and the battery board switch is off. I got around 100mV on both ends of R7. R40/41 measures about 1ohm