Hisense 55A7GQ no audio: HDMI ARC not working diagnosis

⚠️ SAFETY WARNING / SERIOUS RISK. This appliance operates with critically dangerous components (High Voltages, Temperatures, or Gases). Improvised self-repair of critical devices can be fatal or prohibited by law. Physical intervention requires qualified specialized technicians to issue compliant safety certificates. ReeFix provides this diagnosis EXCLUSIVELY for educational and informational purposes.

HIGH PRIORITY

Main Board Failure (Motherboard) - Probability: 60-70%

The main board is the brain of the Hisense 55A7GQ TV, managing all functions, including audio and HDMI ARC. A defect here blocks audio from all sources and prevents ARC from working correctly.

• Key signs/indicators:
  • Total absence of audio from internal speakers and HDMI ARC.
  • The TV does not recognize devices connected via HDMI ARC or does not allow selecting the external audio output.
  • No sound from internal apps (Netflix, YouTube) or digital TV.
• Why it often happens: Often, a Hisense TV with non-functional ARC and no audio has a problem with the HDMI chip or the audio processor on the main board. This can be caused by power surges, component wear, or manufacturing defects.
• Quick checks (user)::
  1. Unplug the TV from power for 5 minutes, then reconnect and try again.
  2. Perform a factory reset of the TV (this might resolve software issues that simulate a hardware failure).
• Estimated costs: The replacement of the TV Hisense 55A7GQ Main Board can cost between 80€ and 180€ for the part, plus 50€-100€ for professional labor.

MEDIUM PRIORITY

Power Supply Board or Firmware Issues - Probability: 25-35%

An unstable power supply or corrupted software can compromise the functioning of audio and HDMI circuits.

• Power Supply Board - Probability: 20-25%
  • Key signs/indicators: Intermittent audio, TV restarting unexpectedly, other visual malfunctions (e.g., dim backlight). In some cases, swollen capacitors on the board.
  • Why: An unstable power supply to the main board circuits can cause logical errors or prevent the audio/HDMI chips from functioning correctly.
  • Counter-examples: If the TV works perfectly except for the audio, and does not experience restarts or other problems, the power supply is less likely.
  • Estimated costs: The replacement of the TV Hisense 55A7GQ Power Supply Board costs between 40€ and 90€ for the part, plus labor.
• Software/Firmware Issue - Probability: 8-12%
  • Key signs/indicators: The problem arose after a software update, factory reset temporarily resolves it, or audio settings are locked/unavailable.
  • Why: Firmware bugs or an incomplete installation can corrupt audio drivers or HDMI ARC management.
  • Quick checks (user):
    1. Check if there are firmware updates available for your Hisense 55A7GQ and install them.
    2. Repeat the factory reset.

LOW PRIORITY

Defective HDMI Cable or External Audio Device - Probability: <5%

These causes are the easiest to rule out and often do not imply an internal TV fault.

• Key signs/indicators: Audio from the TV's internal speakers works correctly, but HDMI ARC with the external device does not.
• Quick checks (user):
  1. Try replacing the HDMI ARC cable with a Certified HDMI 2.0 or higher cable (not all cheap cables properly support ARC/CEC).
  2. If possible, test the TV with another ARC-compatible audio device (e.g., another soundbar or AV receiver).
• Common errors: Using low-quality or non-certified HDMI cables, which can cause handshake and ARC communication issues.
• Estimated costs: A good quality HDMI cable costs between 10€ and 30€.

Output for technician: Hisense 55A7GQ TV with no audio from all sources and non-functional HDMI ARC. Suspect main board failure (audio/HDMI circuit) with high probability. Check voltages on power supply and main board, visually inspect components (capacitors, HDMI chip), and test with firmware reset.

Operational decision: If quick checks (reset, cable change) do not resolve the issue and audio is absent from all sources, consult a technician for main board diagnosis. If the repair cost exceeds 50% of the value of an equivalent new TV, consider replacement.