The Emerson‑Rittenhouse M7000 is an industrial intercom/radio unit that combines a built‑in AM/FM receiver with a local speaker/amplifier for room‑to‑room and broadcast communication. Common failure modes include loss of audio output or radio reception while the master indicator remains lit, often due to a failed RF front‑end, damaged amplifier circuitry, or degraded power supply rails. Other typical issues are loose wiring at the intercom jacks, burnt capacitors on the main board, or a corrupted firmware image that disables communication protocols. First‑check diagnostics: verify 12 V/24 V input and regulator output with an oscilloscope; inspect all solder joints and connectors for cold solder or corrosion; and read any stored error codes from the unit’s diagnostic LED or serial interface to pinpoint the fault source.[oss-gpt-20b]