Display showing scanlines/stripes

Discussion in 'Support Area' started by 1313Q, Jul 27, 2018.

  1. 1313Q

    1313Q Still Fresh

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    About 2 weeks ago, I noticed my Original 256 MB Pandora shows scanline-type vertical stripes from the moment it is booted. It shows during OS use and any other programs too. The color green is unaffected, white is less affected, and all the other colors show strong stripes (picture attached).

    The stripes are especially visible on blue and red colors.

    I opened my Pandora and reseated the LCD cable, but there is no difference.


    pandora vertical lines.jpg

    As a side note, when I opened my Pandora, I discovered that the bottom 2 screws in the case can not be removed from the back plate. No amount of twisting takes them out. They can be unscrewed from the main body, but they will not come out of the back plate (the part that covers the battery). Picture also attached.

    Does anyone know if this is a sign that my PCB is dying? If that is the problem, I can order a new one and replace it, however I will also need a new back-plate and screws. If it is my LCD that is dying, then I don't know what to do.

    screw stuck in back plate.jpg
     
  2. levi

    levi Still fresh, damnit!

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    I don't know the exact LCD cable layout, but loss in green resolution I've seen before. The vertical banding could also be a resolution issue if words that are passed along the lines span a pair of pixels, which certainly used to be common and may still be the case in a number of graphical modes.

    So I think replacing your LCD cable will probably resolve all your graphical troubles. Sent it to ingolstadt to get it sorted, and don't do what I did which is to get ED to send me an LCD cable which on the third time round I shorted out my LCD backlight, and ended up disconnecting my LCD entirely just to get the unit to boot again. In terms of the screws, yes I had the same issue - I think the tolerance on those tunnels is very tight and when they were also painted the screws will go in with a positive force from a screwdriver working with the positive force from the threads but when you're unscrewing them, I managed to completely destroy the aluminium heads on the bottom screws of my Pandora, so I drilled them out and replaced them with generic laptop screws.
     
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  3. TeDaDeS

    TeDaDeS Very Active Member

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    My guess would also be the LCD cable, but that is only based on my first thought.
    The LCD cable for the Pandora has been redesigned because it would eventually fail but I'm not sure if this banding is caused by a defective cable. I would assume it could but that assumption is not based on any facts.
     
  4. levi

    levi Still fresh, damnit!

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    I would guess it can. That screenshot shows it's a 16bpp mode, which I assume is eight bits for green and four each for red and blue. You've lost alternate bits of red and blue and at least a quarter of the low green bits. If the bits are alternated such that if capital RGB represent the left pixel and lower-case rgb represents the next one to the right, so the layout is sent as RRBBGgGgrrrbbGgG or something like that, a trace gap cutting off the right hand 8 bits would give you something like this, although to be fair that's an artificial meshing I made to fit the pattern, and I can't think of a logical reason to actually do it like that. Equally as well it could be a memory map issue, or a tiler problem, but given the Pandora LCD cables are known to have a best before date (especially the earlier ones) then my money's on that until proven otherwise.
     
  5. 1313Q

    1313Q Still Fresh

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    thanks for the replies! I'll send it to Ingolstadt when i get the chance.
     
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