Specifications

Sound Out
No sound from either internal or external speakers
1. Verify volume setting is correct in system preferences.
2. Replace the external speakers or headphone in question with a known-good device.
3. Reset parameter RAM. Press Command-Option-P-R during startup before “Welcome to Macintosh”
appears.
4. Verify internal speaker cable is connected.
5. Replace the internal speaker.
6. Replace the logic board.
Sound Out Symptom Charts
iMac (Flat Panel) Troubleshooting - 23