I went to mod my SNES today to allow it to play the Super Gameboy 2 and when I finished putting everything back together, I am getting a yellow tinted screen. It has been months since I played on the SNES but the picture was fine last time I used it. I did not test it today before pulling it apart.
Colors using a composite cable are correct, and if I use this RGB cable with a different SNES the colors are fine there too. I assume that means there is some issue between the blue mulit out and where it would connect to the cable, but I don't really know where to start.
Is this most likely a capacitor issue? I dont see have the mod could have affected color, but maybe someone has other thoughts?
Any help is appreciated. I do have experience modding/soldering consoles so I am not scared to get my hands dirty here, but this would be my first time trying to fix a SNES.
Fixing yellow screen on RGB 1chip SNES
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NewSchoolBoxer
- Posts: 369
- Joined: Fri Jun 21, 2019 2:53 pm
- Location: Atlanta, GA
Re: Fixing yellow screen on RGB 1chip SNES
You should state the exact mod you installed on the exact SNES console, as in, the CHIP description on the PCB.
So a yellow tint, with light's color by addition, yellow is red + green. That you used the cable with a different SNES rules out a pair of R, G, B connectors being swapped. I think means blue is undervolted on your console or mod. I found a Reddit thread with yellow tint on PVM due to a short in the CRT itself. That's good you pointed out composite works since that rules out other possibilities.
Is this just with Super Gameboy 2 or every game? Do you see the yellow tint with white background and background and does tint ever get better or worse based on background colors?
There was a SNES mod that gave bad picture and it turns out one of the resistors that came in the kit was the wrong value. Double check all resistor and capacitor values. Hopefully you got 1% tolerance resistors. You should also check all the solder joints and the continuity.
Going with blue undervolted idea, possibilities I can think of include:
-Short circuit on the blue line
-Resistor / capacitor wrong value on the mod
-Bad solder joint on the mod
-Capacitor leak on the PCB messed up a trace on the video line
-Aged capacitors on the console that worked better a few months ago that need to be replaced
-Aged PPU that you can't do anything about besides transplant a new one
Possible work around is a cheap 1 video line color amp that doubles the amplitude. Amp up the blue but would want to verify the need on an oscilloscope first. A 25 MHz bandwidth oscilloscope is sufficient for 15 kHz gaming here.
If you can't fix the tint, s-video is a very solid option on SNES. Could take the mod out (is it reversible or do you cut PCB trace?) and see if RGB works again to narrow down the yellow source.
So a yellow tint, with light's color by addition, yellow is red + green. That you used the cable with a different SNES rules out a pair of R, G, B connectors being swapped. I think means blue is undervolted on your console or mod. I found a Reddit thread with yellow tint on PVM due to a short in the CRT itself. That's good you pointed out composite works since that rules out other possibilities.
Is this just with Super Gameboy 2 or every game? Do you see the yellow tint with white background and background and does tint ever get better or worse based on background colors?
There was a SNES mod that gave bad picture and it turns out one of the resistors that came in the kit was the wrong value. Double check all resistor and capacitor values. Hopefully you got 1% tolerance resistors. You should also check all the solder joints and the continuity.
Going with blue undervolted idea, possibilities I can think of include:
-Short circuit on the blue line
-Resistor / capacitor wrong value on the mod
-Bad solder joint on the mod
-Capacitor leak on the PCB messed up a trace on the video line
-Aged capacitors on the console that worked better a few months ago that need to be replaced
-Aged PPU that you can't do anything about besides transplant a new one
Possible work around is a cheap 1 video line color amp that doubles the amplitude. Amp up the blue but would want to verify the need on an oscilloscope first. A 25 MHz bandwidth oscilloscope is sufficient for 15 kHz gaming here.
If you can't fix the tint, s-video is a very solid option on SNES. Could take the mod out (is it reversible or do you cut PCB trace?) and see if RGB works again to narrow down the yellow source.