The Fortron/Source SLD20W is a compact switching‑mode power supply rated for AC 100–120 V input and providing 5 V/4 A or 12 V/0.1 A outputs, commonly used to power industrial control boards and small servo drives. Typical failure modes include degraded output voltage due to worn MOSFETs or rectifier diodes, overheating of the internal heat sink, or a failed main transformer winding that causes over‑voltage spikes on the DC side. First‑check diagnostics should begin with verifying the AC input voltage and measuring the 5 V/12 V rails for correct output under load; inspect the PCB for burn marks, swollen electrolytics, or loose solder joints; then review any error codes from connected controllers that may indicate a power supply fault.[oss-gpt-20b]