Picture problem in s-video

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Don't Panic. Please wash hands.
  • Hello,

    I recently bought (1 week ago) a C64R but i am having problems with the S-VIDEO picture.

    The colors are not contained, when looking at the green, there are red parts and runny overflows.

    I put a display comparison photo of the C64R and a Commodore 64 breadbin with the same graphics chip (see url below).

    The image of the C64 breadbin is cleaner, the colors are more contained (the green doesn't overflow).

    The test is done on the same Philips monitor and the same S-VIDEO cable (din to scart).

    The recognition of the TOD is automatic, I tested it at 50Hz but that does not solve the problem

    Is there a solution to this problem?

    Thanks in advance.


    ttps://ibb.co/XV5v2MC

  • First, please upload the pictures to the forum (attach to your post), dont use external image hosters.


    Then, it looks like the C64Reloaded produces a much more saturated Picture than your breadbin, which makes comparing them like this a bit pointless - try to adjust the saturation of the monitor so both pictures are equally saturated, chances are they will look very similar (including those artefacts) then.


    > The recognition of the TOD is automatic, I tested it at 50Hz but that does not solve the problem


    And i have no idea what this is supposed to mean at all - what does the TOD have to do with this?

  • Hello Tobias


    Thanks for your answer.


    For picture i did't see a option to upload it at my post, sorry.


    My saturation monitor is correctly adjust, It doesn't solve anything.

    It's normal to compare the image of the two machines Breadbin and C64R when using the same video chip. For me, it's a C64 and I expect to have the same quality image and there is no artefacts on the breadbin.

    What I ask is a solution to no longer have this defect ? Either the board is defective or it is a design flaw.


    I did other tests with the game "Big Mac: The Mad Maintenance Man". The character is normally in yellow. On the C64R the character flashes from yellow to green when moving forward ...


    For The TOD See our WIKI ->

    proper 50/60Hz signal for the CIA TOD clocks is generated on board depending on selected video mode. The time base for this is another crystal oscillator, which is running independent of the main C64 clock circuit.


    I said to myself that this could possibly influence the picture.


    Regards.

  • Quote

    It's normal to compare the image of the two machines Breadbin and C64R when using the same video chip. For me, it's a C64 and I expect to have the same quality image and there is no artefacts on the breadbin.

    Different boards produce different video output - this is true even for the different original C64 boards, no matter what videochip is in it. So to compare the images, you'll have to either dial down the saturation when the C64Reloaded is used, or increase it when the C64 is used (so the saturation is about the same for both) - because with (too) high saturation the artefacts you are seing are not unusual.


    That said, can you test with another display and not using a scart adapter? What you describes sounds a bit like that scart adapter is mixing chroma+luma into composite, which also might explain what you are seeing.


    Generally the Picture of the C64Reloaded should be at least as good as with any other C64 Board - so if it is not, its likely something like a broken cable, or broken connector.


    Quote

    proper 50/60Hz signal for the CIA TOD clocks is generated on board depending on selected video mode. The time base for this is another crystal oscillator, which is running independent of the main C64 clock circuit.


    I said to myself that this could possibly influence the picture.

    No, that only means that if a PAL VICII is used, then it will use 50Hz TOD clock, and when NTSC VICII is used, it will use 60Hz TOD clock - none of that affects the image in any way though.

  • Hello Tobia,


    I made several adjustments on my monitor with the contrasts with my old commodre and I don't have the interfaces as on the MK2 C64R.

    Suppose my cable is faulty so explain to me why I have a good image with my old commodore. I tested with a multimeter my s-video cable and all connection is good and my monitor is working fine.


    Regards.

  • Not contrast, but saturation ("color") :) Simply said, "contrast" controls luma, "saturation" (or "color") controls chroma. In your pictures the colors of the c64 reloaded look much more saturated than the ones from the c64 - which is a bit strange. The reason could simply be different output levels however, which is why i asked you to turn down saturation for the c64r a bit, so its the same as with the breadbin.


    As for the cable, i am just guessing here. There is a common problem with using SCART, which is that either inside the adapter, or even inside the monitor, chroma+luma is recombined into composite.


    Also, are you absolutely sure that adapter actually connects chroma and luma to the scart adapter, and not composite and chroma (or luma)? That will also kindof work, depending on how the levels of the respective signals are (and this varies from board to board).


    Thats why i asked if you can test with a different display and without using a SCART adapter - it takes some uncertainties out of the equation.

  • Hello,


    My cable is built according to this diagram.
    Pin 1 of the din is well connected for luminance but there isn't 300 ohm resistor on pin 6.

    Because I read on your wiki that there was a resistor at 3300ohm installed in the chrominance on s-video.
    Now is this 3300ohm resistance also installed on the din 8 - pin 6 ?

    Or is there a specific wiring in din 8 for the C64R?


    Thanks

    Regards.

  • Now is this 3300ohm resistance also installed on the din 8 - pin 6 ?

    No - the additional resistor is ONLY in the S-Video output. The original output has exactly the same lavels as the original machine. That explains the elevated Chroma level that you're observing.