Whelen UPS‑64LXA is a 75 W strobe light power supply with four universal outlets and selectable Hi/Lo outputs, commonly used on emergency vehicles for high‑intensity lighting. Known failure modes include internal regulator burnout or capacitor degradation leading to output voltage sag, overheating of the heat sink, and failure of the built‑in fuses or protection diodes; the unit is discontinued so spare parts are limited. First‑check steps: verify input voltage (13.5–26.5 VDC) and measure each outlet for correct regulated output, inspect the heat sink and fan for dust buildup, and examine the internal fuse and capacitor assemblies for signs of burn or leakage before attempting reflow or component replacement.[oss-gpt-20b]