Sony pvm 20M2MDU wrong colors


Twinkle Star Sprite
I recently got this very dirty pvm for free (was sitting outside). Before turning it on I cleaned out the inside a little bit. At first it had the correct back background with the white menu. Now the background is white with green letters for the menu. Sometime if I blow air in the back the color of the picture would change. Anyone have a idea how to fix this?