The Bycan PS‑2850 is a dual‑purpose aircraft ramp power supply and battery charger that delivers a filtered 28 V DC output up to 50 A for testing avionics and recharging run‑down batteries. Common failure points in this class include blown input fuses, degraded filter capacitors, relay wear in the switching circuitry, and internal diode or rectifier damage from over‑voltage spikes. Begin troubleshooting by verifying the AC mains supply (220 V/60 Hz) and checking the main fuse; then measure the 28 V output under no load to confirm proper filtering and current capability; finally inspect the battery charger mode for correct operation and any fault LEDs or error codes displayed on the unit’s panel.[oss-gpt-20b]