What's going on

The Sony X90L is a standout model in the Sony Bravia XR LED lineup, but HDMI ARC/eARC communication glitches remain a common headache. When the audio return channel breaks down, you might experience complete silence, volume control failure, or an annoying audio latency delay between the TV and your soundbar or home theater receiver.

Unlike traditional audio connections, eARC relies on continuous two-way digital handshakes managed by HDMI-CEC protocol (which Sony labels Bravia Sync). When either the software stack or physical link stumbles, the TV usually falls back to its internal speakers or throws an "Audio System Error" message.

Symptoms people notice

• Total silence when sending sound through HDMI 3 (eARC/ARC).
• Audio playing fine for several minutes, then dropping out intermittently.
• The TV remote no longer changes the soundbar volume level.
• The X90L defaults to internal TV speakers every time you power it on.
• Significant lip-sync errors when streaming content with Dolby Atmos sound.

Likely causes

• Handshake Failure: A temporary software mismatch between the TV's Google TV operating system and the soundbar software.
• Incorrect Input: Using HDMI ports 1, 2, or 4, which lack eARC hardware integration.
• Cable Bandwidth Deficit: Using an older HDMI cable incapable of maintaining the bandwidth necessary for eARC passthrough.
• OS Memory Glitch: Stale system processes in the TV's firmware hindering audio routing.
• Wrong Digital Output Mode: Conflicting output settings when processing multi-channel surround signals.

Quick checks first

1. Check the Label: Make sure your cable is plugged into HDMI 3. Ports 1 and 2 are standard HDMI 2.0/2.1 inputs without eARC audio return capabilities.
2. Toggle Audio Passthrough: Head into Settings > Display & Sound > Audio Output. Switch Speakers to Audio System and set eARC Mode to Auto.
3. Swap the HDMI Cable: Replace your cable with an Ultra High Speed 48Gbps cable to eliminate physical line noise or bandwidth degradation as the culprit.
4. Test Internal Apps: See if the issue persists across different streaming apps or externally connected devices like gaming consoles to isolate audio signal errors. Check our general TV hardware troubleshooting guide for broader diagnostics.

When it's a real hardware fault

If performing hard power resets and changing HDMI cables yields no results, you may be facing a hardware-level failure on the TV's mainboard. Physical damage to the pins inside HDMI Port 3, blown static discharge filters near the HDMI controller chip, or corrupted board firmware can permanently disable eARC capabilities.

Hardware failures on modern smart TVs typically require swapping the main system board rather than soldering micro-components. Read hardware performance comparisons in our hardware reviews hub to gauge whether replacement components or external optical audio adapters make the most sense for your setup.

Soft resets vs board/panel work

Soft resets and software re-configurations are safe, non-destructive steps every owner should perform before seeking technical service:

• Safe to do yourself: Unplugging cables, power-cycling the TV, toggling Bravia Sync settings, changing audio output formats (PCM vs. Auto), and updating TV system firmware.
• Requires Caution or Professional Hardware Repair: Disassembling the back chassis of the X90L, testing mainboard circuit continuity with a multimeter, or replacing internal circuit boards. Avoid opening the TV cabinet unless you are qualified, as high voltage hazards persist near internal power boards.

Next steps

Start by executing a full HDMI power cycle—unplugging all HDMI leads and disconnecting power from both the TV and soundbar for 5 minutes. If sound is still not returning, verify your system software is up to date via Settings > System > About > System Software Update. If the port itself is physically damaged or failing electronically, using the optical audio output port is a reliable temporary workaround while evaluating board repair options.