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Bias settings-Sony 10HT

Discussion in 'Projectors, Screens & Video Processors' started by Johnty, Oct 23, 2001.

  1. Johnty

    Johnty
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    Have sony stopped displaying the bias settings in the service menu. My Pj only gives me the gain values and Rom version (1.03)

    Is there something I`m not doing to find the bias values? Where do I find these values?

    I note that the RED value is 187 for all colour temp settings.Why do Sony set this at the 70% mark? For optimum picture, FAQ(thebigpicture) recommends increasing this to 255.Will doing this limit any later increase required to compensate for drop in LCD efficiency? or do LCDs not drop efficiency during lifespan?

    All help appreciated.

    John
     
  2. minimivic

    minimivic
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    Have you gone into the service menu?
     
  3. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Not sure if this is cheeky but to get to the bias settings you go to the service menu then, once you've got gains on screen just use the down arrow to scroll to the bias adjustment.

    Hope this works!

    Gordon
     
  4. slingshot

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    Mine's the same ROM version and I get the bias settings (never touched them though). It isn't something silly like they only get displayed when using certain inputs, i can't see why but some of the settings only get displayed when selecting a relevant output.

    I don't know why Sony set the gain so low, maybe Gordon can offer an explanation, but I haven't heard about the setting affecting lamp or LCD panel life.

    Cheers

    Slingshot
     
  5. Johnty

    Johnty
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    Thanks Paul,Gordon and Slingshot for replies.

    You`re right Gordon I did not realise need to scroll down to read bias
    settings.

    Any comment on max gain setting: have all those with the Sony10HT set their
    RED gain to 255 and recalibrated green and blue settings for optimum
    greyscale?

    I`m told that LCD panels control light throughput ,so a higher gain value eg
    255 will not geneate as much heat in the panel which must be a good thing.

    Also note that composite gain settings for RED are much higher.Is there a reason for this?

    John
     
  6. minimivic

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    I set red to 255 then the others to compensate. Worked really well, but took a lot of time to get it spot on by eye. Gordon has the test equipment to do this corrctly ( I believe ) but you should get a good result anyway.

    If you get really brave you can adjust the colour unifirmity across the screen but I didnt :D
     
  7. LV426

    LV426
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    I've recalibrated by gains, twice. The safest thing to do is to set your own values in one of the customer colours that you wouldn't otherwise want to use - that way, if you don't like what you've done, you can simply revert to one of the other (unchanged) colours. Also - write down factory numbers before you begin to tweak.

    I said "twice". I started out by simply increasing red to 255 and then others to compensate, as described. This DID have the effect of increasing contrast.

    The second time was following some advice on www.thebigpicturedvd.com As suggested there, I bought a red colour correcting filter (CC20R - cost £10.50 in p&p) and attached it to the front of the lens. This has the effect of

    a) making the blacks in the picture about half as bright (guess)
    b) making the entire picture pink (of course).

    So, I changed another custom colour, again with red at 255 and the others to compensate (higher values than before) to regain a properly coloured image. Lo and behold - even more contrast, and much better blacks.

    The easiest way IMHO to balance the colours by EYE is to use a black and white image (not a test signal - a picture; I used part of "Pleasantville").
     
  8. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    I do have test equipment to do this. I have never had a customers unit set with gain at max on red after calibration. At least I'm pretty sure I haven't.....

    If you want to do it by eye then ideally you need a source of 6500K white light. You need to compare your "grey" to it. The eye has auto white balance built in to your brain so by just looking at a bluey grey image or a greeny grey one your brain will start to see what is wrong as "right" as it works out it's supposed to be grey.

    I would use 40 IRE and 80 ire grey window patterns off AVIA or V.E. for this task. With a CRT projector you might want to try 40IRE and 70 IRE. With an LCD perhaps 30 AND 80.

    Anyway, do what ;LV246 says and write it all down and work on a USER defineable setting rather than a factory default.

    Have fun.

    Gordon
     

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