I recently replaced the original bulb/enclosure in my Samsung HLP4674 after 9700 hours, but the new one(s) seem much dimmer. Bulb #2 is physically smaller, but enclosure #2 has the same markings as the original [BP96-00224C(P)]. The retailer was kind enough to offer a replacement, suspecting that bulb #2 was bad. Bulb #3 is the same as bulb #2 (100W/120V Philips, the same as shown on the larger bulb #1), and enclosure #3 again has the same markings.

So I have three bulbs with 3 different measures of light output at 100 IRE:
#1 back in 2006 measured 282 cd/m^2 (82 fl!)
#2 measured about 40 cd/m^2
#3 measured about 37 cd/m^2

I suspect that the new bulbs need a higher-wattage ballast, or that the set's ballast isn't what it used to be. Can ballasts degrade without failing? Can this set accommodate a higher-wattage ballast?

I recall that the old bulb let me watch TV during the day without too much trouble, but with the new bulbs I now have to draw the shades. I've read postings that say these TVs should output somewhere between 10 and 50 footlamberts (34-170 cd/m^2), but that range goes from lousy to plenty. What amount of light output can I reasonably expect to get out of this TV?