The Richardson Electronics NL392 is a high‑current AC‑to‑DC power supply module commonly used to feed industrial drives, motor controllers and other heavy‑load electronics. Common failure modes for this class of units include overheating of the main transformer or rectifier bridge, degradation of input filter capacitors, and failure of the internal MOSFETs or switching diodes due to overvoltage or ripple spikes. Initial troubleshooting should verify that the unit receives correct line voltage (±10 % tolerance), check output voltage under no‑load and full‑load conditions with a calibrated multimeter, and inspect for visible signs of component damage such as bulging capacitors, burnt traces, or melted solder joints. If the supply passes these checks but still fails to energize downstream equipment, examine the control logic and any protective shutdown signals that may be tripping the unit.[oss-gpt-20b]