The lock seems to be on PCM, 48K.

There are still dropouts. Oddly, when I use the DirecTV TIVO replay feature (a few seconds back) the signal does NOT drop out in the same place. It appears that good signal is available on the hard disk.

The dropouts happen at irregular intervals even during a continuously played program and not at commercial/program transitions.

Oh, based on reviews at your web site Gonk, I got my only other current digital audio source, my Samgsung HD931. It does not have digital dropouts. (Btw, at $209 from Amazon is a great deal for 950 owners. No 5.1 analog outputs, no dolby or dts decoders in it, so you don't pay for what you paid the 950 to do. And yes, you do get DVI output.)

I suppose I could try switching to a different digital audio in port, just to see if Optical 1 is fritzed, but not the others. (Only optical from the DirecTivo, no coax)