Controller display is blank or very dim; solar system does not respond.

Safety: Use a non-contact voltage tester and turn off power before opening the controller.

• Check breaker: Verify the circuit breaker or GFCI feeding the controller is not tripped. Reset if necessary.
• Test line voltage: With caution, measure voltage at the controller input terminals. If none, trace back to the source.
• Inspect internal fuse: Open the controller and look for a replaceable fuse. If blown, replace with the same type and rating after identifying and correcting the cause.
• Check transformer or supply: If line voltage is present but the display is dead, the internal power supply or transformer may have failed, requiring controller replacement.