Short the green wire (PS_ON) to any black wire (Ground).
A shorted diode at the output of the standby transformer can also kill the standby rail. If the standby IC looks physically intact, technicians often check these diodes first. How to Test the PS-4241-9HA ps42419ha schematic work
Professional technicians often use a DIY Test Box with a series lamp (60W/200W) to prevent catastrophic shorts during testing. Short the green wire (PS_ON) to any black wire (Ground)
Repairs typically center on the standby voltage circuit, which is the most frequent source of failure in the PS-4241-9HA. ps42419ha schematic work
A small resistor often acts as a fuse for the standby IC. If the IC shorts, this resistor usually burns out as well.