Sharp XG-E3000U lamp dimming

I've been using this projector for about 6 months with no problems until last night. It was working fine for about 90 min, then the lamp suddenly dimmed to about half brightness and I could hear a buzzing noise similar to the sound it makes when the lamp is first starting. I immediately shut it down for about 5-10 min. After powering it on again it worked for about 55 min before doing the same thing.

The lamp was used when I got it, so I don't know how many hours are on it. Does this sound like the lamp may be failing?

I've seen two of these projectors with bad power supplies and only one with a good power supply (this one). Are there any known causes for the high failure rate? Is there anything I can do to prevent it? Both of the bad power supplies had a burnt out inductor and shorted power MOSFETs in the lamp supply. It uses the same power supply as the XG-E1200U and XG-E3500U.

I have the projector apart right now to clean the filters and check for obvious problems. Andy Cuffe

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Andy Cuffe
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After putting it back together the lamp didn't even try to start. I checked the lamp start circuit and found a shorted thyristor. I'm guessing the lamp was dimming because the start circuit was activating while the lamp was running.

The bad part is a Toshiba SF8JZ47. I subbed it with an NTE 5558 and it seems to be working fine again.

Andy Cuffe

snipped-for-privacy@gmail.com

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Andy Cuffe

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