The Branson 8400 is an industrial ultrasonic power supply used in plastic welding and cleaning systems, delivering up to 900 W at a 20‑kHz output frequency with a 230 V AC input. Common failure modes include transformer winding insulation breakdown, rectifier diode or bridge failures, electrolytic capacitor degradation leading to voltage ripple, and overheating of the internal cooling fan or heat sink. First‑check diagnostics should verify the input mains voltage and continuity through the power transformer; then measure the DC output rail under load for correct voltage and ripple levels; finally inspect the rectifier bridge, capacitors, and cooling fan for signs of wear or failure.[oss-gpt-20b]