Elmo XP‑550 is a 16 mm xenon arc projector equipped with a 550 W lamp and an integrated 50 W sound amplifier. Common failure modes include lamp burnout or poor contact in the bulb socket, failure of the built‑in power supply (especially after cold‑start upgrades), motor drive issues on the synchronous reel mechanism, and degradation of the amplifier circuitry. First‑check diagnostics: verify mains voltage and proper grounding; inspect the xenon bulb socket for corrosion or loose connections; test the internal power supply output with a multimeter; confirm that the amplifier’s input jack and speaker outputs are functioning before proceeding to motor drive troubleshooting.[oss-gpt-20b]