GNB Industrial Battery Co. SMPS 48V/15A is a high‑current switch‑mode power supply used to feed industrial drives, controllers, and battery chargers with a stable 48 V DC output. Common failure modes for this class include degraded electrolytic capacitors, transformer winding insulation breakdown, MOSFET or IGBT burnout from over‑temperature or voltage spikes, and fan or heatsink overheating that limits cooling. Initial diagnostics should verify the AC input voltage and phase balance, measure the regulated 48 V output with a multimeter while monitoring temperature, inspect all electrolytic capacitors for bulging or leakage, and check the integrity of the power MOSFETs and any protection fuses. If these checks reveal anomalies, proceed to component‑level testing of the switching stage and transformer windings.[oss-gpt-20b]