Lock MK II Type 9 Power Supply is a rugged industrial DC supply designed to power electromagnetic locks and related access‑control devices, typically featuring an input range of 110–240 VAC and a fused output rated around 5 A/250 V. Common failure modes for this class include fuse blowouts, capacitor degradation in the rectifier/filter stage, and insulation breakdown between high‑voltage input and low‑voltage output. Initial checks should verify that the unit receives proper line voltage and that the output regulator is within spec using a multimeter; inspect all fuses and visual signs of overheating or burn marks on PCB traces; and review any error codes or indicator LEDs for indications of overcurrent or short‑circuit protection activation.[oss-gpt-20b]