SNES RF/Multiout video output (wavy lines)

[Brachabre]

I bought a strange snes (model# shvc-cpu-01) off of craigslist for fairly cheap and of course has a problem. I would like to know if anyone can remedy or pintpoint what could be causing this kind of "wavy line" video output my bastard of a son SNES using both multiout/RF.

Video Output description:
Using RF, game starts great and then about 10 minutes in I start notice wavy lines that gradually get worse and worse and start to move in patterns that usually move in a single direction. Games are perfectly playable despite graphic output looking like shit. The multiout is much worse: 1) Same wavy line problem, but also has 2) dull colors and 3) every minute or so the current screen frame does a burst of jittery movements (translations) up and down like an old-fashioned movie projector, and finally 4) witnessing doubling effect on foreground sprites (ie. Street Fighter two or more Guiles) every 30 seconds or so. The game logic is perfectly fine through all this however so i'm pretty sure it's not the cpu.


Basic tests:
AC Adaptor - works on my original SNES no problems
Multiout RCA cables - works on my N64 no problems
Nintendo coax RF adaptor (grey) - assume it's okay b/c same wavy lines appear using multiout (already mentioned those cables good)
Two known-to-be-working SNES games - scrubbed contacts with alcohol/qtips

Advanced tests:
On two separate occasions: Thorough pass with Qtips/alcohol over every nook/cranny/solder joint/cartridge slot (credit card wrapped in alcohol'd eye lens microfiber cloth). No corrosion, rust, charred areas, liquid or physical damage. All solder joints look shiny and great.

Reflowed solder: All RF joints, all multi-out AV joints, all solder joints on the bottom of the modular SHVC sound card, some other random hole-through caps, and tried to reflow solder around a few of the surface mount caps by the rf/multiout video output area

RF output 10 minutes into any game:



All this has done jack shit in alleviating my video output problem. I would like to test the caps, but do not have the appropriate instrument. I would just replace the caps if I had a little more confidence that it could be the cause of my issue. I love to salvage things whenever possible so this is worth it to me to try and salvage this thing. Thanks.