There are a couple of Threads over on the Matrox X-100 forum related to JVC HR-DVS2U and DVS3U decks which have developed a major firewire transfer problem which manifests itself as 'sub-frame' pixelation (i.e., within a single frame there are corrupt pixels)
Below are some links to this problem.

- Actual good/bad frame pics
http://finalsmoke.com/matrox/

- Text threads
http://forum.matrox.com/cgi-bin/rtx100/ultimatebb.cgi?ubb=get_topic;f=11;t=001127
http://forum.matrox.com/cgi-bin/rtx100/ultimatebb.cgi?ubb=get_topic;f=11;t=000832

Anyone have any ideas on this?