What is wrong with my SNES?

[Hendrik Stephanson]

Hello,

Recently I bought a Snes with 4 games through the dutch equivalent of Ebay. It's a PAL version. When I started playing I noticed weird errors on screen with all the games. I attached some pictures so you can see how it looks.
The games adventures of mighty max and super soccer work fine, only the startup screen is messed up. With Timon and Pumba's jungle games the error is constant on both the startup screen and while playing for example pinball. The game Asterix is even weirder. The starting screen is messed up and while playing there is nothing I can walk on, but when I jump up I suddenly stand on a tree and the environment shows. The background doesn't seem to be in sync with the game, as I can stand on air.

Things I've tried:
1. With the Snes came a 3rd party AC adaptor with 9volts and 800mA, not the right one I found out while searching on the internet. I borrowed an original Snes adaptor from my brother with 9volts and 1300mA. Unfortunately the same problem still exists. So that possibility is ruled out.
2. I tried different TV's with no luck, I used a new composite video cable(with red, white and yellow pins). I even used the original rf switch to plug it in an older TV from the 90's, but still the same errors.
3. I borrowed the game Donkey kong from my brother which works fine on his Snes, but that game won't even startup on my Snes. When I switch the nintendo on it says on the tv it can't find a signal.
4. I cleaned all the games with a q-tip and alcohol. I also put some cloth on a creditcard with alcohol and cleaned the inside of the console itself.

It has to be something inside the Snes. It seems the problem is only showing while there is non moving background like in the game menu.
The seller won't reimburse so I'll have to fix the problem on my own.

Do you have any idea of what could be the problem?

Thanks,
Stephan

I uploaded the pictures in this link so I could upload them all at once:

http://share.pho.to/4aOJk