Charger shows E20 and the display indicates a contactor test failure; unit will not energize output.

Safety: The contactor switches high current. Turn OFF the breaker and verify no voltage is present before inspection.

• 1. Listen for contactor operation:
  • When starting a charge (before E20 appears), listen for a distinct click from inside the charger.
  • No click suggests a coil or drive issue; a continuous hum or repeated clicking suggests mechanical problems.
• 2. Internal inspection:
  • Open the charger and locate the main contactor on the power board.
  • Check coil connections and feedback wiring.
• 3. Electrical tests (qualified only):
  • Measure coil resistance to confirm it is within spec.
  • Check continuity across contacts when the contactor is commanded ON (per AMPROAD test procedure).
• 4. Replace faulty parts:
  • If the contactor is defective or welded, replace the AMPROAD power board or contactor assembly.
  • If the drive circuit is faulty, replace the power board.
• 5. Retest: After replacement, run the built-in self-test (if available) and confirm E20 is cleared.