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WTD: Variable pot thingy to adjust Component voltage

Discussion in 'Home Cinema Building DIY' started by nathan_silly, Sep 17, 2003.

  1. nathan_silly

    nathan_silly
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    Since my RP has Red Push- and I believe is uncorrectable in the service menus, I would like something like the attached picture.

    Basically it'll fit to the back of the DVD player on the red component output, and it'll have a variable pot to adjust (the voltage?)- and on the other side a female RCE - in which the RCA cable to the RP pushes into.

    I could then adjust the pot to get the right red balance.

    Will this work?- will it sort out the colour decoder value? Or would it just bring out the greyscale?

    Is it doing the same thing as RDRV/RCUT or the front Screen VR pots?

    Blooming annoying if Red Push can't be fixed by any means.

    Ta
     
  2. nathan_silly

    nathan_silly
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    whoops forget picture.
     

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  3. nathan_silly

    nathan_silly
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    Just thinking- the blue & green are also out (not as bad) so could I use one of these on each lead to get the Avia colour decoder test correct?

    And how would I adjust tint per gun?

    Thanks
     
  4. Mr.D

    Mr.D
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    I don't think it will work.
    The output is YUV remember not RGB. You'd have to map the YUV into RGB to get control over the R level. I can't see a way of doing it in YUV colourspace.

    It might be possible in RGB but I doubt you'd get the right respose curve you need for correct adjustment in a variable resistor. Also I suspect you don't get redpush with RGB as it bypasses the colour decoder ( depends on TV I suppose).

    Only accurate way I can think to do it would be to use a PC and perform a real time colour correction on the red response curve on the overlay ( this is quite an intensive operation and I'm not even sure if any of the major hardware manufacturers support seperate RGB curve manipulation on the overlay).

    There is those ACE colour corrector box things but I again I don't know if it offers seperate RGB controls that would be any use.

    tint ( hue) isn't a function of the gun its down to the colour decoder transformation>
     
  5. nathan_silly

    nathan_silly
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    Damn and blast :(
     
  6. Steve.EX

    Steve.EX
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    Nathan

    Is the RPTV a Tosh?
    If this is the case then control over the red gun is available via service menu.
    R drive
    R cut

    these, of course will have overlapping effects on temperature and greyscale etc.


    Steven
     
  7. nathan_silly

    nathan_silly
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    Yup- it's a Toshiba.

    Do you know what setting this is then? (it's not RDRV or RCUT)
     
  8. Steve.EX

    Steve.EX
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    Nathan.

    I would say it is Rdrv and Rcut, make notes as to original values and tread carefully, this, particularly rcut if i recal correctly can have a rather dramatic effect.

    I will look for the link to a most informative DIY rptv site, however as Mr. D has stated, when mucking about with what effectively will be colour temp and greyscale it is quite "unusual" to attempt it without instrumentation.

    Steven
     
  9. nathan_silly

    nathan_silly
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    But I'm pretty sure the greyscale is OK- the Avia greyscale bar is neutral gray and white is white.

    It's just when there's red- that's it's too red. See attached pic. The top has been reduced in the Red saturation only (selected reds in photoshop and then reduced) - decreased below the accurate settings just to give a contrast to the bottom one..

    the bottom one- which is similar to the display my set- all non-red colours look fine, there is no red sheen to the image (white does not look murky white-red) I've selected Reds in photoshop and increased saturation.
     

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  10. Steve.EX

    Steve.EX
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    Nathan

    Dare i suggest S-Vid?

    If not, why not drop the red drive a tad.


    Steven
     
  11. Mr.D

    Mr.D
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    Adjusting the Red cut-off and drive will make everything more cyan. It won't help the red push.
     

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