Sony Sony HT-S400 2.1-Channel Soundbar with Wireless Subwoofer NO POWER Error Fix: Soundbar Won't Turn On

Error code NO POWER on the Sony Sony HT-S400 2.1-Channel Soundbar with Wireless Subwoofer means: Soundbar Won't Turn On. The soundbar does not respond to the power button on the unit or the remote control. No indicator LEDs illuminate on the front panel. Verify the AC power cable is firmly connected at both the soundbar end and the wall outlet end. Test the outlet by plugging in another device. Try a different outlet. Unplug the soundbar power cable for 60 seconds to reset, then reconnect firmly. If the standby LED was previously visible and has now gone dark, the internal power supply may have failed — this requires professional repair or warranty service. If the soundbar was connected to a power strip, surge protector, or smart plug, try connecting directly to a wall outlet to rule out the power strip as the cause. Check that the power cable itself is not damaged.

The most successful fix is "Test and Replace Internal Power Supply" (hard difficulty, ~60 minutes). Estimated DIY cost: $0-$20. HomeMD has 2 community-ranked fixes for this error.

This error is rated high severity. You should address it promptly — continued use could cause damage or safety concerns.

Yes — the top-ranked community fix ("Test and Replace Internal Power Supply") is rated hard difficulty and takes about 60 minutes. Tools needed: T10 Torx screwdriver, Multimeter, Plastic pry tool.

DIY cost: $0-$20. Professional repair typically costs $120-$200. Many homeowners save money by trying the top-ranked community fix first.

The Sony Sony HT-S400 2.1-Channel Soundbar with Wireless Subwoofer has 8 other known error codes, including: AUDIO DELAY (Lip Sync / Audio-Video Delay), AUTO STANDBY (Unexpected Power Off / Auto Standby), BT PAIR FAIL (Bluetooth Pairing Failure), CEC CONFLICT (HDMI CEC / BRAVIA Sync Erratic Behavior), DISTORTED AUDIO (Crackling, Popping, or Distorted Sound), and 3 more.

Error code NO POWER also appears on 2 other Sony models: Sony HT-A5000 5.1.2-Channel Soundbar with Dolby Atmos and DTS:X, Sony HT-A7000 7.1.2-Channel Soundbar with Dolby Atmos and DTS:X. The fix may vary by model, so check each model's specific page for tailored repair steps.