I bought my TH-50PX50U in 2006 and I've never touched (or even considered) the firmware on the unit. Even though it's working fine I figure that almost 4 years later something may have improved or changed and that it may be worth my time (no idea how) to update the firmware.
I've always had this little problem which is that on every DVD movie (HDMI) I watch I get 2-3 seconds of static on the plasma at some point. When that happens the DVD player's screen reads "no HDMI signal". I always thought it was an older DVD player I had but I feel certain it's the TV since it does it with the new DVD player (even though it's the same Moster HDMI cable). But I've always lived with it since the warranty is long gone and sending it to get fixed at 100lb. is not worth the time and $$, IMO.
PX50U + same HDMI cable + new DVD player = problem.
Why do you not think the expensive Monster cable is bad? Is the 50U hooked up to a cable/sat box with an HDMI cable? If so, switch cables and see what happens. If you don't have another cable, you can try a $4 one from a vendor like MonoPrice before concluding that the TV is at fault.
I suspect it's the Monster HDMI cable only if my Panasonic was not defective from the beginning. I'll have to get off my a$$ and change cable just as an experiment, but I haven't because my only HDMI connection on the 2006 50PX is in the back and the thing weighs so much it's a hassle calling a friend for help. I only have the DVD player connected via HDMI and the first DVD player was a Samsung HDMI 1080 up converter which passed on to the kids play room (and does not do it there). The newer DVD player is an Onkyo 1080 up converter and still the same thing happens for 2-3 seconds at least ones during a 2 hour movie. I've learned to live with it but since I just ordered a 4 port HDMI switch with a couple of new HDMI cable I'll be able to confirm whether it's the cable or just the HDMI connection on my TV.
Any thoughts on my looking to upgrade the firmware after 4 years?