That's quite an interesting setup. HDMI doesn't work well beyond 10m without a repeater or signal booster, so running it over 2 CAT5 cables is pretty clever.
I don't think EMI is going to be the culprit here, although that may also depend on the amount of EMI within the cabinet. Even many of the inexpensive cables are shielded properly, but I don't know what the effect of EMI would be on the screen, and I'm curious to know if the effects of additional EMI would cause your symptom.
You might test this theory by connecting the unit directly to the television via straight HDMI for a few days to see if the same symptom happens. If not, it may be interference or a limitation within the cabling. That's probably the best way to verify the player, or isolate the symptom.
I recently purchased a Samsung BD-P1600 after reading many reviews and looking at many players. The unit is great - excellent picture, etc.
I've had it up and running for about a week - on the 2nd day I started having a problem where the television screen will suddenly flash to an all white screen of static/snow. After a bunch of trouble shooting, checking cables, etc. I figured out that if I leave the power on to both the unit and television and unplug the HDMI cable and then reinsert it - everything returns to normal. (for various amounts of time (10mins - 2days) before it does it again). It happens while viewing discs or streaming content. It would appear to be some sort of cabling issue... I am using an HDMI over CAT5 extender setup - but only over about 20 feet of cabling as the components are setup in an A/V closet with only the display on the wall. The HDMI setup sends the signal over 2 CAT5 cables and has an active indicator (red or green lights) that indicate the setup is working correctly (even when the screen goes to snow). I'm using two 3' CAT2 HDMI cables, one on each end of the extender setup for the player and television connection.
Basically my question to the forum is: is there anyway to verify that the player is "ok" and that it is in fact a cabling / EMI problem. Secondly, the CAT5 cables are run by themselves (no power near them). Could the EMI actually be on the HDMI cables in the A/V cabinet or behind the display.
I have other inputs into the television, S-Video and Component from other devices and there is no issues w/ them - only the HDMI connected Samsung player.
Thanks for taking the time to read this lengthy post - any thoughts/help is appreciated.