I have a 8300HD purchased from CostCo (the 320gb model). Over the past few months a problem has developed and worsened to the point where the unit is essentially useless.

Basically, playing back recorded video results in horrible, lurching stutters, varying from audio dropouts to completely unwatchabe video. The picture never actually breaks up with garbage, it just plays 10 frames, pauses for a second, plays a half second, pauses unresponsive for 15 seconds, and so forth. Kind of like trying to play video over a crummy internet connection. This seems to happen with automatic recordings made on every channel but does NOT appear to affect timeshifting.

Recordings do seem to complete fine, but I suspect the issue is actually with the recording versus the playback as several very old recordings from February play back just fine.

Thoughts? Hard drive write head failure? Tuner or encoder failure? Has anyone seen anything like this before?

Symptoms point to hard drive failure. If it's rented or purchased and still under warranty, watch what you can and swap for a new one. If it's purchased and out of warranty put in a new drive. Lots of info on that here on Digital Home.

Heh, looks like large PATA hard drives are a PITA to find! However I discovered that I still have 3 months warranty remaining.

In the box there was a little pamphlet of how to deal with service, both in and out of the 2 year warranty period, including first calling Rogers who was supposed to verify the unit was dead and then direct you to a CostCo store for an exchange. Not surprisingly, the person on the phone was completely oblivious to the CostCo warranty process and knew absolutely nothing about how the return/swap procedure is supposed to be handled (especially their part in it all), beyond saying that I could swap it direct with Rogers for a refurbished 8300.

However if I read the CostCo warranty card correctly, if I take it in store they will simply swap it for another new unit. The 8300 is obviously no longer available to buy new... does that mean they'd swap with one of the new ones? Not that the feedback on those is so great...