Do LCD RPTV Bulbs Go Bad?

[Josuah]

So I have to change my LCD front projector bulb every 2000 hours. And I can noticeably tell that the bulb quality is degrading every 500 hours in or so. But does the same hold true for the bulb in an LCD RPTV?

IIRC, Sears will replace the bulb if it blows up while under warranty, but there's no mention in the manual about having to order a new bulb, opening up the case, and replacing the bulb. Also, the picture quality doesn't seem to degrade the same way the front projector does. Either it degrades much more gradually so it's not as noticeable, or it just doesn't. Possibly because the light is not reflecting off the screen but passing through it.

[lcaillo]

Front projectors typically have lamp life rated for about 2000 hours. RP systems are typically several times longer due to the lower power ratings on the lamps. There is a drop in output through the life of the lamp and more severe just before the lamp fails, but it would generally not be noticed at 25% of the life of the lamp. If you are seeing the picture degrade, it is likely due to needing some cleaning in the light path on a 3 chip system.

[Josuah]

Hm, well I don't think I want to be opening up my LCD RPTV, but it's probably been used about 4000 hours. Thanks for the info. It's good to know.

[lcaillo]

What brand of set do you use? The need for cleaning the optical path inside the light engine is the dirty little secret of three-chip systems.

[Josuah]

I've got a Panasonic PT50LC13. 50" that I bought in early 2004.

[lcaillo]

Put full field red, green, and blue fields up and check each one for uniformity. If there are any abnormalities at all, you likely need the light path cleaned, especially if the blue has any problems.

[Josuah]

Meaning if there are some parts that look less or more green than others, to the naked eye looking dead on? I'll give it a shot.

[lcaillo]

Yes, do it for each color.

[Josuah]

Everything seems to look okay.

[AverageJoe]

Josuah wrote:

I've got a Panasonic PT50LC13. 50" that I bought in early 2004.

I have the same set (well, I gave it to my son last week when we bought a new plasma), and I replaced the lamp late last year after about 4500 hrs. Panasonic had given 10,000 hrs as the estimated lamp life, but I felt pretty lucky since some people had replaced their lamp twice by then. Panasonic extended the lamp warranty to 18 months on that model, apparently due to so many early failures. They also offered a $1000 rebate toward a new set (of at least $1500) if you had three lamp-related failures within the warranty period.

Since you're at 4000 hours and out of warranty, you might consider buying a replacement lamp to have on hand. It's a single slide in module so they're easy to replace (but cost about $300 - Model# TY-LA1000).

[Josuah]

Eh, most likely if the lamp blows up we'll just take it to recycle or something.