VideoHelp Forum
+ Reply to Thread
Results 1 to 11 of 11
Thread
  1. Hi there,
    I just joined hoping to find some answers. I just moved my upstairs hi def cable box motorola to a new floor for use with my panasonic viera plasma tv.
    When I used the unit yesterday (with different cables) the unit was fully functioning, hd channels worked on cable box, today after setting up on new tv, hd channels are scrambled, and tv signal is only in Black and White. picture is there (though black and white ) only and audio is there.
    I would not have thought the new comp video cable I used has an issue, but I know the cable box worked yesterday, and on all other inputs (blu ray, netflix, youtube) the tv is on colour. When I plugged the cable tv cable directly in the back of the tv it was in colour.
    Any idea why?

    Graham

    Canada
    Quote Quote  
  2. Member Cornucopia's Avatar
    Join Date: Oct 2001
    Location: Deep in the Heart of Texas
    Search Comp PM
    You don't have the cables plugged in to the correct jacks.

    BD -> TV

    R_ -> R_
    G_ -> G_
    B_ -> B_

    will look ok, but

    R_ -> U_
    G_ -> Y_
    B_ -> V_

    will look ~just like your B&W problem.

    "Component" could mean RGB, or it could mean YUV - even if the cable/jack coloring is the same.

    Read the fine manual first, and if that doesn't clear things up, post pictures of your setup along with model #s of your equipment.

    Scott
    "When will the rhetorical questions end?!" - George Carlin
    Quote Quote  
  3. Okay thanks Cornucopia, I did look at the manual and don't see anything unless I am missing something...
    My panasonic viera plasma is a tcp60ut50, I did try as you suggested changing the comp video cables on the cable box as the tv only has rgb inputs not the YUV you mentioned. When I did that I lost all picture- I then checked the order of RGB to what was labelled on both the cable box and the TV and still only have black and white and no HD channels... my cable box is a motorola dct 6200.
    Any more suggestions?

    Graham
    Attached Images  
    Quote Quote  
  4. Member
    Join Date: Jun 2012
    Location: USA
    Search Comp PM
    Originally Posted by grahamstuart View Post
    the tv only has rgb inputs not the YUV you mentioned.
    Graham
    According to the manual (pg. 18) Cornucopia is correct. Of course, according to pg 10 of your cable box manual, you are outputting Y, PB, PR as well.

    Have you gone through the menus on both the TV and the cable box to be sure they are set up to output and receive the proper signals?
    Last edited by smrpix; 8th Aug 2014 at 15:50.
    Quote Quote  
  5. Member Cornucopia's Avatar
    Join Date: Oct 2001
    Location: Deep in the Heart of Texas
    Search Comp PM
    If you look closely on both the TV and the Cable box, the component jacks are lableled:

    1. "Y" (for Luma) = Y -> usually the Green cable
    2. "Pb" (for Chroma of Luma-Blue) = V -> usually the Blue cable (also equivalent to Cb when so labeled)
    3. "Pr" (for Chroma of Luma-Red) = U -> usually the Red cable (also equivalent to Cr when so labeled)

    That YUV was what I was referring to earlier.

    So it should have been set up:

    BDP Y -> (G) -> TV Y
    BDP Pb -> (B) -> TV Pb
    BDP Pr -> (R) -> TV Pr

    If that was the way it was set up, it SHOULD have been working. (And my assumption of incorrect connection was mistaken because you chose to refer to them as RGB when they aren't).

    Unless one or more of the cables is bad.

    I have often seen a color image turn to B/W with an iffy cable that lost its signal in the Pb and/or Pr.
    The "Y" luma cable transmits the B/W portion, so it sounds like that is still working.

    If that's what's going on, IIWY I'd buy a newer/better set of cables.

    Scott
    "When will the rhetorical questions end?!" - George Carlin
    Quote Quote  
  6. You can test your cable by connecting each of the pairs in turn between the green output on the cable box to the green input on the TV (the green connector is the Y signal which carries the greyscale picture and the sync signals). If you get a greyscale picture with each then the cable is fine.
    Quote Quote  
  7. Member Cornucopia's Avatar
    Join Date: Oct 2001
    Location: Deep in the Heart of Texas
    Search Comp PM
    ...And if the cable does prove to be fine, there is something else going on with your output->input intefacing. I'd think it would be much easier just to get an HDMI cable and hook them up that way instead.

    Scott
    "When will the rhetorical questions end?!" - George Carlin
    Quote Quote  
  8. Some devices use the same channel for both composite video and Y channel of component video. With those devices you have to specify whether the signal is composite or component. So make sure the cable box is set to output component video, and the TV is set to component input.
    Quote Quote  
  9. Member Cornucopia's Avatar
    Join Date: Oct 2001
    Location: Deep in the Heart of Texas
    Search Comp PM
    Yep, that's it.

    A jack expecting a composite signal, but being given a Luma (Y) signal, would be in B/W. Just need to switch it in your menu (Video/Component input option).

    Scott
    "When will the rhetorical questions end?!" - George Carlin
    Quote Quote  
  10. Conversely, a jack expecting a component signal but getting a composite signal would display a B/W image.
    Quote Quote  
  11. Member Cornucopia's Avatar
    Join Date: Oct 2001
    Location: Deep in the Heart of Texas
    Search Comp PM
    Yes, that's true. But I don't think it likely in this scenario.

    Scott
    "When will the rhetorical questions end?!" - George Carlin
    Quote Quote