I've recently encountered a strange issue. I had a Time Warner Samsung HD Cable Box connected to my 52" Samsung HD LCD via HDMI. I have an optical running from the cable box to my Yamaha 663 A/V receiver. When watching cable TV, I had the receiver set to SURROUND DECODE and it would play Dolby Digital 5.1 on the channels that had it (HD channels) and for the 2 channel channels it would use ProLogic. Fast forward 2 months and all of a sudden the receiver no longer plays Dolby Digital 5.1 for those same channels it previously did - now it uses ProLogic for all channels. I did some troubleshooting and discovered that when I pull the HDMI cable out of the TV - then the receiver will play dolby digital 5.1 instead of ProLogic - but of course then I have no picture on the TV. I thought it might be an issue with the cable box so I went ahead and exchanged it for a Scientific Atlantic HD DVR and I still encountered this same problem. I can't connect the receiver to the tv via hdmi because of handshake issues so im at a loss here as to why this happened or how to fix it - any help would be greatly appreciated - thanks.