The SQM‑150‑1422 is a 120/240 VAC industrial power supply used to provide regulated DC output for Switching Systems International control panels and servo drives. Common failure modes in this series include electrolytic capacitor degradation on the rectifier/filter stage, transformer winding insulation breakdown leading to shorted secondary turns, and overheating of the internal switching regulator that can cause output voltage drift or intermittent shutdowns. Begin troubleshooting by verifying input mains voltage and polarity with a multimeter, then measure the DC output rails for correct voltage and ripple; inspect the heat‑sink and surrounding area for excessive temperature rise or burnt components. If the supply passes these checks, perform an isolation test of the transformer secondary to detect any shorted turns, and finally replace suspect capacitors or the regulator IC if diagnostics indicate component failure.[oss-gpt-20b]