The Yokogawa GA‑500 is a handheld refrigerant gas analyzer designed to detect and quantify gases such as R12, R134a, and R22 with high accuracy using infrared or tunable diode laser spectroscopy. Common failure points for this class of portable analyzers include power supply degradation (battery or AC adapter), sensor drift or contamination in the optical path, and internal calibration memory corruption that can trigger self‑diagnostic alerts. Begin troubleshooting by verifying the unit’s voltage input and battery charge level, inspecting the probe and optical window for dirt or damage, and reviewing any error codes displayed on the LCD to isolate sensor versus firmware issues.[oss-gpt-20b]