Tools Required

RMS Multimeter with Diode Test Mode.

Step 1: Power Down and Lockout

Ensure the system is fully de-energized:
- Turn off the CCR (or disconnect mains power if PSUV system)
- Engage lockout/tagout before touching any internal circuitry

Step 2: Identify and Disconnect Wires

Locate the bridge rectifier
Identify the red and black wires connected to the rectifier’s output terminals.
Mark or note wire positions before disconnecting.
Disconnect only the output wires (DC side), not the AC input side.
Note: The positive (+) terminal is usually rotated 90° from the others and is connected to the red wire. The black wire connects to the negative (–) terminal, diagonally placed from the positive.

Step 3: Perform Diode Test

Set your multimeter to Diode Test Mode.
Place the black (–) multimeter lead on the positive (+) terminal.
Place the red (+) multimeter lead on the negative (–) terminal (opposite corner).

Step 4: Evaluate Results

Meter Reading | Condition
~0.90V–1.00VDC | ✅ Bridge Rectifier is Good
~0.40V–0.60VDC | ❌ Bridge Rectifier is Bad – Replace It

Safety Reminder

Always maintain safe working conditions by using appropriate personal protective equipment (PPE) where necessary.
Only qualified service personnel should perform bridge rectifier testing on airfield lighting systems.
Follow lock out / tag out procedures and verify absence of hazardous voltage before handling internal circuitry or junction box components.

Airport Lighting Company | Troubleshooting Instruction