Game Gear LCD problem, also how do you open a GG cart?

[izarate]

I got a GG at a flea market but there is something wrong with the LCD:

With no game:


With game (Wonderboy):




I'm using an oficial MK2103 AC adapter. The GG seems to run the game fine, the sound is good and the "graphics" on the LCD move an change colors. The horizontal lines on the LCD change places each time I turn the GG on, so it doesn't seem to be stuck pixels or anything.

Could this be fixed with new capacitors? As far as I know, replacing the capacitors just fix sound and fading LCDs, isn't it?




By the way, how do you open a Game Gear cartridge? I removed the screw on the back but I can't take it apart.
EDIT: I managed to open it. Damned tabs!!!

Well, cleaning the cart didn't do anything.