Super Famicom Audio/Video Issues

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  • July 4, 2020 at 8:43 PM #39514
    ariyasu
    Participant

      Hello, I am using a Super Famicom with a RGB Scart cable from retrogamingcables.co.uk
      I have it hooked up to the AV1 Scart socket on the OSSC. The OSSC is running firmware 0.86a. When
      I play games and there is a dark scene, I see vertical bars across the entire screen, They are present
      in every scene but less noticible unless it’s black/dark.

      The second issue I have audio is always buzzing, humming and clicking, at all times in all games,
      please check the first video for an example. I have tested the SFC connected directly to a SDTV and
      it plays great with no audio issues and a clean image (see second video).

      Can anyone help or offer some suggestions. I am running out of ideas.

      OSSC SFC Audio/Video Issues Video

      SFC Direct Connection to SDTV, No Issues Video

      Scart
      Lines on dark scene 1
      Lines on dark scene 2

      July 4, 2020 at 10:36 PM #39517
      eatnumber1
      Participant

        Looks like jailbars
        https://shmups.system11.org/viewtopic.php?f=6&t=62631

        Also have a look through the google results for “SNES jailbars” to get more info.

        May 2, 2022 at 6:10 PM #53170
        ariyasu
        Participant

          Hello all again and sorry to bump an old post but I fixed the issue today and thought I would share the solution.

          First I did a full system recap and the problem was still there.
          Then I added 10uf decoupling capacitors to C90 to C95 as suggested in the link eatnumber1 posted above. This also did not fix the issue.

          This weekend was a bank holiday so I decided to mess around with it again and see If i could get it going. A user on discord suggested I try
          a different power supply, so I tried a Sega Mega Drive power brick, and the ugly vertical lines I had became ugly diagonal lines. This gave
          me something new to google for and I found this post by FirebrandX
          https://shmups.system11.org/viewtopic.php?f=6&t=43689&p=1312908&hilit=snes+apu+subcarrier#p1312908

          My Super Famicom had a diffrent board version than the one listed in the post. Mine is SNS-CPU-RGB-01 instead of APU-01,
          but I figured I would try it anyway. After lifting the leg and testing the image is crystal clear 🙂 so I am very happy
          and now I am off to play though Zelda.

          TL:DR Lift leg 3 of PPU-2 to fix awful RGB interferance on SNS-CPU-RGB-01 and APU-01 boards.

          View post on imgur.com

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