Attempted to RGB Bypass SHVC-CPU-01 Super Famicom. Picture too bright.

Discussion in 'Modding and Hacking - Consoles and Electronics' started by syboxez, Oct 9, 2016.

  1. syboxez

    syboxez Active Member

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    So I got some of borti4938's RGB Bypass PCBs for 3CHIP consoles, populated, replaced the resistors and removed the transistors on the SNES, soldered it all in, and the end result is a picture so bright that it messes with my TV's sync at some points, and whites become pink, etc. Now this would generally be an easy fix, that being putting some resistors on the RGB lines, but I don't know what values would give me the correct colors.

    https://i.imgur.com/LziaJlB.jpg

    Using this: https://github.com/borti4938/SNES-AddOn-PCBs/tree/master/RGB Bypass/3Chip-SNES
     
  2. borti4938

    borti4938 Robust Member

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    The description there is for the PAL version of the 3Chip-SNES. The schematic of the NTSC and PAL SNESes is totally different. Therefore the 'bypass' works differently.
    I don't have a SHVC-CPU-01, so I just can give a guess how I would install the THS7314 on this mainboard.[​IMG]
    I hope that this schematic is correct for the SHVC-CPU-01.
     
  3. syboxez

    syboxez Active Member

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    That worked perfectly! Thank you.

    You may want to update your git repo to include instructions for NTSC systems. I'll do the mod to my other SNES now (I was doing it on my Super Famicom as a test).

    EDIT: Actually, something went very wrong. Now some games (Final Fantasy VI) is randomly losing sync mid gameplay. This happens both with composite and RGB (using CSync). It might be hanging because one time it lost sync at the beginning of FFVI intro, then got it back, but the audio was ahead of the game. Did I mess up the mod, or is something else wrong? I'm not doing this mod on my other SNES unless I can figure this out.

    EDIT:
    Picture of mod: http://i.imgur.com/wr5yCxn.jpg (please excuse my awful SMD soldering skills)
    Video of sync issue: http://www107.zippyshare.com/v/FfvACttc/file.html

    EDIT2: This is on an SD2SNES, by the way, and it doesn't seem to be happening on Yoshi's Island, so maybe it's a power draw issue? I'm using a 9v 2A switch mode PSU, so amperage shouldn't be an issue.

    EDIT3: I may have fixed it by putting a 2200uF cap on the 7805 (yes, I know it's overkill, but it's what I had). I will do more testing before I say it's working 100%.

    EDIT4: Just tested for quite a bit with several things (looping the FFVI intro, SNES Burn in test, Yoshi's Island gameplay) with no hiccups. I think I can safely say it's fixed.
     
    Last edited: Oct 9, 2016
  4. borti4938

    borti4938 Robust Member

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    I have considered that in my last update :) Thanks for reporting!
    https://github.com/borti4938/SNES-AddOn-PCBs/blob/master/RGB Bypass/3Chip_SNES_README.txt#L46

    It seems that your PSU is not well regulated. You may consider to replace your PSU...
     
  5. syboxez

    syboxez Active Member

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    Using my Game Gear PSU with my other SNES that I modded (replaced the barrel). Now there is zero interference and zero issues. Turns out I got a cheap switch mode power supply.

    Any idea where I can get new linear supplies or switch mode supplies that are stable and don't produce noise? I don't mind paying a bit extra for one that's properly produced.

    The only problem now is that I seem to be getting jailbars in the picture. This happened before the mod as well.

    Also I took pictures of the process and may post a tutorial here if you don't mind, this time with much better soldering.
     
  6. unmaker

    unmaker Newly Registered

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    That would be awesome, as I was considering attempting this mod. But I have to ask though, what is the benefit of doing it? I've read that this mod does not produce a sharper RGB image but that it makes it look "better". What does that mean exactly, improved color clarity?
     
  7. syboxez

    syboxez Active Member

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    I did it because of the low pass filter built into the amp. It cuts out a lot of the crap that's in the image.
     
  8. Ergot_Cholera

    Ergot_Cholera Flaccid Member

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    I have a SFC with SNS-CPU-APU-01 and it has horrible diagonal interference on RGB. Where are the points xactly on the underside where I take the signals from for RGB bypass?
     
  9. borti4938

    borti4938 Robust Member

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    Ergot_Cholera and zeruel85 like this.
  10. Ergot_Cholera

    Ergot_Cholera Flaccid Member

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    Ohhh...I thought it might fix it. What were you playing at Nintendo?!
     
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