Tekbilt Inc. 30820 C2203889 is a 12‑amp, 5‑volt switching power supply with either a single red LED or dual‑color indicator; it uses a Mean Well MWP‑602/MWP‑602A equivalent circuit. Known failure modes include intermittent operation caused by the 270 kΩ/½W resistors R4 and R8 degrading over time, as well as general switching regulator issues such as capacitor leakage or fan failure in older units. First‑check diagnostics should verify the power‑on LED status, measure output voltage under load, and test R4/R8 for continuity and correct resistance; also inspect for visible overheating or damaged capacitors on the board. If these checks are normal, proceed to evaluate the main switching IC and input/output connectors for signs of wear or arcing.[oss-gpt-20b]