Cassette Deck · Sony · TC-230

Diagnosis: Protection Relay Won't Click

The receiver is staying in protection mode or its speaker relay is not engaging.

Safe first checks

Disconnect all speakers and speaker wires, then power the unit on again.
Wait at least 10 seconds; some receivers delay the relay at startup.
If the relay engages with speakers disconnected, inspect the speaker wiring for a short.
If it never engages, do not connect speakers until a technician checks the amplifier for DC offset or a power-supply fault.

Next step

The next diagnostic stage should record whether the relay clicks with no speakers attached and whether any protection indicator is lit.

Bench Technician Steps

This is the model of work a qualified electronics technician follows using the exact service manual and suitable test equipment. It is not a do-it-yourself instruction to work on energized equipment.

With speakers disconnected, verify the protection circuit, relay contacts, output-stage devices, and power-supply rails against the model-specific service documentation.
Check for excessive DC at the amplifier outputs and investigate any imbalance before reconnecting speakers.
Verify the relay-drive and protection-sense circuit only after the amplifier and supply stages have been evaluated safely.