After having successfully replaced all of the capacitors, and having given this system a fresh coat of paint...would it work properly again? My Japanese import of Yoshi's Island had just arrived in the mail, and it might help me test my system. Here's how my testing progressed...
Well...the title screen looks great! I see no graphical glitches at all. Entering a level, however, there's definitely some color bleed.
At this point, it's not really clear whether there is still a serious problem or not. In the particular level I am testing with there are drawbridge-like panels in the back wall which fall forward and attempt to crush you. More advanced graphics methods are used to simulate this in three dimensions. An interesting thing happens as I approach one such panel. The screen severely darkens when the SNES tries to load and render the three-dimensional wall section. The screen remains darkened as long as that panel is loaded. When I walk past that area and it unloads that section of the level the screen returns to normal brightness.
So, clearly, the capacitor replacement did NOT fix the graphics issues. The PPU (Picture Processing Unit) seems to have a more serious issue. At this point, it's time to do a more thorough test. I purchased a reproduction of the official test cartridge used by Nintendo's service centers. This is my first time using this cartridge, so I do a bit of exploring.
The sound test contained exactly the level of explosions and annoying sound effects that I expected it would, so as to test all sound channels and frequencies. (What I wasn't expecting was test 7, which was a 16-bit rendition of Zelda II's title theme. This same song also loops during the burn-in test. It's far too cheery with these instruments, though.)
Things were fine so far. Now we'll see if the more in-depth burn-in test revealed serious graphics problems or not.
Clearly, the graphics were failing, but only in particular modes or effects. As far as my research showed, there was no reasonable way to fix this sort of problem. So, I had to admit defeat. I painted a great-looking system, but now it was all a waste...
...or...was it? It actually was quite trivial to purchase another Super NES and swap its innards into the one I painted. So in the end I have not just a great-looking Super NES, but a working one!
I learned a lot along the way, and it was enjoyable to work on repairing and revitalizing something like this. I also learned a lot about testing this sort of hardware.
For others who may be wondering if their system is failing, I've embedded the videos below which I took during burn-in testing on both the good and the bad systems.