Replaced lamp broke in Sony KDS-R50XBR1 50" HDTV after 2 minutes
When you say "lamp broke", do you mean the lamp actually physically broke? (as in 'exploded'?)
Was it a Factory replacement bulb, manufactured by Sony? (did it have the Sony logo on the box?) Many "3rd party" lamps are made from inferior materials, made in inferior conditions... and produce inferior results... including what you've mentioned. If this is the case, I suggest getting a replacement, or better a refund, then get a real Sony lamp... personal experience speaking here.
Normal failure mode of the ballast is that it will usually be totally dead, probably 85% of the time. Sometimes you will see one that's struggling to output enough power to maintain proper brightness.
What you describe would be a VERY rare failure, indeed. The ballast can not really burn out the lamp, by design. It's possible the ballast could have been weak, and just now failed... if the lamp still looks to be in good physical condition, this is a possibility, though remote.
BTW... 6 years is pretty good, but it's more about operational hours. I believe those low power lamps should last 5,000 to 8,000 hours, for an original Sony lamp.
Another thing to keep in mind is the lamp cooling. If the fan that cools the lamp has failed, and for some reason the detection circuitry is not realizing that... this could be a problem. These arc lamps operate at about 1200 degrees F (internally), and require a lot of cool air to keep them from literally melting, or exploding.
on Dec 04, 2013