The Rembrandt Sapphire Teeth Whitening System is a chairside bleaching unit that combines a 25 % hydrogen peroxide gel with the Sapphire Plasma Arc Light (PAC) for rapid curing and desensitization. Common failure points in similar dental light‑curing devices include power supply faults, lamp filament burnout or degradation, and electronic control board errors such as over‑temperature shutdowns or faulty sensor inputs. First‑check diagnostics: verify 120 V AC input and confirm the unit’s internal fuse or circuit breaker is intact; inspect the PAC lamp for visible discoloration or a loss of brightness; review any error codes displayed on the touch screen or LED indicator panel, and test the temperature sensor output with a multimeter to ensure it falls within manufacturer specifications.[oss-gpt-20b]