Can anyone help me diagnose a problem with my Nintendo 64?

OK, I have had this unit for many years, I did not use it for many years, it sat in my bedroom for a long time collecting dust. When I got an HDTV, I brought all my game systems out to the living room, had a custom entertainment center built with a space for my N64, and tried to use it. I have only one A/V input on my HDTV, so I used a 4 channel A/V splitter to hook up my N64, my Game Cube, my Wii and my PS2. But the first time I played the N64, it worked for a bit, but when I shut it off and tried to change games, there was no picture.

Every now and then I can get a game to work, but usually I can not. Well, I let the problem go for a while, but then recently when I saw a used N64 in a second hand store for 7 dollars, I decided to buy that and figure out the problem come hell or high water. Basically, this unit did the same thing. Now, this unit came with the N64 and came with the power adapter, but not the A/V cable, so I figured it’s the A/V cable.

So, I was going to get another A/V cable, and when I described the problem to a guy who owns a used video game store, he seemed almost certain that was the issue. But then I saw that GameCube and N64 use the same exact A/V cable, so I tried to use the A/V cable from my GameCube, since I haven’t been using that since I bought the Wii, because the Wii will play my GameCube games. Well, that didn’t work either.

So, I thought, maybe it’s the A/V input to the TV, but I tried each of the other games both through the splitter and directly to the TV and all of them worked, but the N64 would not (just sporadically). I tried both N64s with both A/V cables and both power adapters, and also tried the A/V cable on the Game Cube, got everything else to work, but not the N64 (not consistently) in any configuration.

So, I checked the N64 in every position on the splitter, directly to the TV, and other items in the position the N64 originally held on the splitter, same result.

So I know the N64 gets power, I know they both do. I know the both A/V cables work on the GameCube. I know all 4 positions on my splitter and my A/V line in work on my TV. And I know it’s not isolated to one N64 cartridge because they all do this. My best guess is that maybe the heads on both are dirty and aren’t making contact with the cartridges?

Anyone else run into this, and how did you resolve it?