NES Graphical/Color Problems

I was given a nice, boxed NES toaster for my last birthday. Unfortunately, I have never been able to get the thing to run well. I have issues getting games to boot and when they would, they would never have the full color palette--it was almost grayscale only. I thought the pin connector was bad, so I picked up a replacement from a reputable seller. No dice. Games still would rarely boot up and when they would, it was under a limited color palette. I read into some more fixes and apparently, people have had good success with boiling the OEM connector. Sounded strange, but at this point I had little to lose. Again, no dice. Mind you, all games have been thoroughly cleaned multiple times, likewise with the system's cartridge slot and where it connects to the main PCB. AT this point, I am stumped and am wondering if some chip is on it's way out as I can never get the graphics/colors to be right. Here is some sample pictures taken from Double Dragon 2. Appreciate any help.