SNES Vertical White Bars

[Arithium]

I had my snes modded with a ths7374 and now I seem to be getting a weird issue while using composite and s video where I have vertical white bars. I dont have a way to capture component or rgb but using HD Retrovision component cables I dont have this issue on my hdtv.

The issue seems to be more apparent on images with solid color, I'm using a 3rd party s video cable and 3rd party power supply but I don't have these issues on my regular snes so I don't know if those are the factor.

[RGB0b]

Turn on the 7374's LFP and see if it goes away. Contact your modder for more information.

[Syntax]

Turn on the 7374's LFP and see if it goes away. Contact your modder for more information.

Does not effect S-Video or Composite.

[Arithium]

I had him mod it before with a 7316 and had a clean s video feed. I sent it back to him and he installed the 7374 and I’m experiencing this issue. I just sent it back to him again to see if he can figure out what’s wrong.

[RGB0b]

Turn on the 7374's LFP and see if it goes away. Contact your modder for more information.

Does not effect S-Video or Composite.

LOL, I skipped right over the part where he said composite. Sorry!

[Arithium]

Decided to bump this again since the modder was able to replicate the issue. I'll be forwarding some of the stuff hes done.

So I have been trying to trouble shoot an issue on snes minis

So first let me describe it:
Its cascading up and down lines in the video specifically composite or (modded) S-Video.
The lines appear on dark screens but vary on what specific colors they pop up on from console to console.
These lines do not appear related to the white middle white bar issue.
I've noted that changing the brightness or color of my TV seems to wipe them off of one color only for them to appear on a different set of colors where they weren't present before.
I have looked at the waveform and it appears flat (where its supposed to be) on max white and max black
These lines stay in place.
I put a variable pot on the composite line to ground and was able to adjust the lines on/off only for them to appear on another color set. There was also warping of color flatness . Areas would appear slightly whiter than others and move with the adjustment of the pot.
Appear with/without sound.
Appear across stock 7805, new 7805 and 78S05, also appear with brand new wet caps.
Appear the same across different OEM AC adapters.
Most notably and possibly relevant is they appear on my CRT others CRT's, S-Video capture devices, but do not appear on the XRGB over composite.
I am using 240P test suite on a multicart for testing but I can also see it on real games.
I have tried every fix listed for the white bar fix with no change in result.
Two different consoles here the green is all OEM not changed, blue has every white bar fix out there. The blue one has the lines much the same but its harder to see on camera.

Built an amp so I can confirm its not output impedance and tried a few more cables.
The issue seems to be AT or BEFORE the PPU
The only solution I can thing of possibly is trying a different encoder.

heres a picture I just took of my crt with the color turned down to 0. This is a regular snes 2chip, an sd2snes, OEM AC adapter and composite video.
https://imgur.com/a/TosbI

[Syntax]

Looks similar to the Sega Mega Drive rainbow banding on composite which is caused by the subcarrier being out of spec and the way the stock encoder creates composite.
If you feed an entirely seperate subcarrier signal to the encoder via a crystal oscillator you will probably find they change.

You will probably find using a different composite encoder will fix the issue but cause another one like a fuzzy image.

When I had a play with different encoders for the mega drive each one seemed to have good points and bad points. I gave up.

What confuses me is that you say thete was no issue with the original mod so whats failed since then??

[Arithium]

The issue seemed to be more noticeable on my snes mini than it did on my original snes. As for the initial mod, It may of just been an issue with the lines showing up on a different color, as him changing caps moved the lines to be more noticable on different colors with 240p test suite.

The modder noticed the issue with the brightness/contrast makes it appear more so I changed settings on my tv and realized they were there, just less noticeable.
Upon intial testing I didn't see them simply because of the settings on my tv/capture.

[Arithium]

Update: he was able to diagnose the lines being caused by the clock, but is unsure of the exact location of the cause. As a result of fixing the lines it reduced the super bright s video output on greens.

[Syntax]

Subcarrier signal is derived from the clock so that makes sense.

Was he able to fix it or just diagnose it?

[Arithium]

Subcarrier signal is derived from the clock so that makes sense.

Was he able to fix it or just diagnose it?

He was able to fix the lines, but hes unsure of the exact spot that's causing it. I believe your reply pointed him in the right direction.

[syboxez]

How did the modder fix it? I've been having this issue on all of my SNESs (to varying degrees), and have been looking for a fix for a very long time.