My oldest HR20 has started having problems with the inserted local commercials on Comedy Central, but I'm sure that it's wider spread than that. It affects both recordings and live playback. Live playback has completely crashed the MPEG4 decoder on several occasions now, both for recorded content and live reception, requiring a reboot to fix; MPEG2 is not affected! It appears that the MPEG4 decoder is unable to handle the switch between the local and national feeds. I first saw it during playback of one specific program (@midnight), but I noticed that it was happening day after day in the same commercial break; it appeared as total corruption! By the time the program returned, things had returned to normal. My other, slightly newer, HR20-100 is less affected, but I've seen it there as well (when trying to confirm if it was signal corruption or the DVR). The difference between the 2, including no problem on the newer one most of the time, has convinced me that the problem is aging electronics! My question is this.... Where is the MPEG4 decoder located? If on the motherboard, I'm screwed, it just a matter of time. The tuner boards, however, can be changed out. So, if the decoders are there, maybe that's a fix. As I write this, however, I realize that this is a dumb question. The decoder must be on the motherboard! But I'd still like a confirmation that changing out the tuner cards will probably have no effect!