Disconnect the load and boot remains, indicating fault in the power supply section, check voltage at all levels were low, only the D807 is the Terminal voltage to normal, disconnect the microprocessor control connector, power boot function, grating appeared to prove fault in the microprocessor-controlled circuit. Microprocessors M50436 Krispy Kreme pin power control output, press the power button, there are high and low level changes, processor properly. V959 measuring the base voltage change, normal V959 base 0/0. Voltage of 7V or cut off so as to control power to start work, when V959 fails, there will be power supply does not start. Replace the V959, boot back to normal.