Why does the HDMI pass through mode get cut off after 20-30 seconds?

The pass through mode allows you to output the HDMI signals (such as audio) to the television, even when the receiver is in standby mode.

There are two settings available for European models:
Auto: When the TV is turned on, while the receiver is in standby mode, the receiver outputs HDMI signals from the HDMI OUT jack.
Off: The receiver does not output any HDMI signals when in standby mode.

To take advantage of the pass through mode ensure that:

For Multi Channel AV Receiver:

1. Control for HDMI is set ON
2. Pass Through is set to AUTO
3. The TV is connected via HDMI Output A 
   

For Bravia TV Set:

1. The BRAVIA Sync Control is set to ON
   NOTE: For TVs not manufactured by Sony, the CEC CTRL will carry its own trade name. For further information, we advice to check with the manufactuer of your TV.