When to replace a bulb

Discussion in 'Projectors, Screens & Video Processors' started by stevos, Nov 1, 2017.


    1. stevos

      stevos
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      I don't know if it's because content has generally got darker in decent years (which it has) or if it's the bulb in my projector getting close to the end of its life, but I have found myself turning up the brightness for tv shows recently and darker scenes.

      So my question is, roughly after how many hours do you typically replace your projector bulbs?

      I need to check the exact number of hours on mine but assume somewhere over 1k by now, but probably not by a lot.

      I have a JVC HD350.
       
    2. pRot3us

      pRot3us
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      When it reaches it's recommended life or when the image becomes too dim.

      When you say you've been turning up the brightness, I hope you don't literally mean the brightness control, you should open up the iris as the lamp ages/dims, possibly also switching to high lamp mode (noise permitting). If I recall the HD350 has a limited number of aperture steps (3?) for the iris, but you can fine adjust these from the service menu if needed.
       
    3. kbfern

      kbfern
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      HD350 bulb life is stated as 2000hrs by JVC (not warranted) but that is a theoretical half life when it would be expected to be not bright enough for normal regular use.

      Lamps in reality can last longer or shorter, type of use can make a difference. Long continuous periods of use would normally give longer overall hours where as lots of short use periods (perhaps up to an hour at a time) would generally reduce lamp hours.

      Of course lamps can and do dim early and can start dimming as young as a couple of hundred hours sometimes they can literally go pop it really depends on your luck. As a general rule expect 1000-1500hrs from an HD350 lamp and you will have done ok.

      The dreaded X3/30 series seemed to fair worse with 600-800hrs being the sort of time a lot of lamps died. Later lamps from X35 seem to do better and since X series JVC were saying 4k hours were possible though as already stated X3/30's seemed particularly bad with the early lamps untill V3 or was it v4 that seemed to improve things quite a bit.
       
    4. stevos

      stevos
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      Na not literally the brightness, i just use a different image mode preset, which appears to be less dim but does mean the image itself is a little washed out in the dark scenes.
       
    5. stevos

      stevos
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      this is useful thanks.

      It is kinda annoying though, i don't like if its the lamp or not and throwing a few hundred at a new lamp could go towards a x7500...
       
    6. KelvinS1965

      KelvinS1965
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      I use a modestly priced Lux meter to periodically check my lamp brightness (with a 100% white test pattern) and I've been doing this since the days I had a HD350 myself. It's the only way to know 100% that the lamp has dimmed and then I can open the aperture to compensate.

      I found that after about 600 hours I'd lost a fair bit of brightness and I ended up buying a spare lamp off the classifieds (brand new in box). This second lamp didn't dim quite as quickly, but was still losing output after another 600 hours.

      The other things is that JVCs tend to suffer with gamma droop over time. Without getting too technical it basically means that the brighter parts of the image become washed out and the darker areas tend to get crushed (which loses shadow detail). On the HD350 this can be calibrated out with the built in controls.

      As Keith says the newer models from X35 onwards are improved in this regard, though the gamma droop still happens (at least now there is an autocalibration feature that will correct this with a fairly cheap sensor and free JVC software).
       
    7. stevos

      stevos
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      i checked the lamp usage last night and it's actually lower than I expected at around 750 hours, pretty much all at low lamp mode.

      I will look into the gamma point, although I have never really got the grips with calibrating displays, I tried to learn the basics a few times but never really got anywhere with it.
       
    8. KelvinS1965

      KelvinS1965
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      Mine was all low lamp too, so you're 150 hours more than mine was when I replaced the lamp...the stated figures aren't a guarantee unfortunately.

      Since these don't have an autocal function, then the only option is to manually adjust. You don't need an expensive meter to correct gamma (which IMHO will make the biggest difference on an older JVC), but I found that the free software HFCR was a lot more fiddly than (paid for) Chromapure.

      Might be worth just trying a user mode, setting it to 6500K, Standard HDMI (so contrast and brightness should be correct at 0 if using a BluRay player not a PC) then experiment with different gamma options. They will all be out by now, but you're just looking for the best compromise if you can't calibrate. You can also open up the aperture to the brightest position (you need to go into the service menu to adjust it in smaller steps, so probably safer to stick with user controls).
       
    9. stevos

      stevos
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      it seems you can buy original bulbs in 3rd party casing for reasonably price, so I might just try it out
       

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