Otis · DSD 412 DC Elevator Drive
The Low Voltage Power Supply (A4) output has dropped below 60% of its rated voltage, leading to a drive shutdown. A CPU Reset is required after the cause of the fault has been rectified.
Click steps to track your progress.
Verify the presence of 115V AC input power to the A4 board.
Check for short circuits in the +5V, +/-15V, and +24V circuits, inspecting both internal and external connections.
Inspect any internal fuses of the A4 power supply for continuity and replace if blown.
If all other causes are ruled out, replace the A4 Power Supply PCB.
Perform a CPU reset on the Drive Control PCB after addressing the fault.