Astec MP4‑1Q‑1U‑1U‑1V‑1V‑03 (73‑540‑4022) is a modular switch‑mode power supply providing 24 V, 60 V, and 85 V outputs from an 85–264 VAC input. Common failure points for this class include degraded capacitors on the rectifier side, burnt or loose MOSFETs in the output stage, and over‑current protection trips due to shorted load lines. First‑check diagnostics: verify input voltage and polarity with a multimeter; inspect all electrolytic capacitors for bulging or leakage and replace any that are suspect; test each output rail against its rated voltage while monitoring for dropout or oscillation; finally review the PSU’s status LEDs or fault codes (if present) to confirm whether protection circuits have been engaged.[oss-gpt-20b]