I have a PS3 Slim which is used only as a media centre (no games) linked to an Onkyo TX-NR609 receiver and Samsung 55D6600 TV. After the recent PS3 firmware upgrade to v4.0 I get momentary drop outs in the sound when playing a bluray in standard Dolby 5.1. The HDMI indicator flashes on the receiver as it re-establishes the connection but there is no interruption to the picture. Changing the output on the PS3 to PCM seems to eliminate the problem, although it has happened once or twice. The fault does not appear to happen with DVDs or streaming video with PS3 Media Server, nor with blurays with DTS.

I may be quick to blame the PS3 as both the TV and Receiver are comparatively new and I cannot be certain that I played a bluray with DD before the new firmware but I'm pretty sure I have. Both the TV and receiver have current firmware.

Does anyone have any ideas? I've googled widely and can't find anyone with a similar problem, although that may be down to my search criteria.