I cannot get my imported games to work in color.
That' normal if you try to watch any PAL video source on a NTSC standard TV or vice versa, you will see all the image b/w because NTSC System and  PAL system use a different color encoding. To solve this problem you should replace your original video cable with a RGB cable.... 

Game appears in Black-and-White on the TV Screen:
If you try to watch any PAL video source on a NTSC standard TV or vice versa, you will see all the image b/w because NTSC System and  PAL system use a different color encoding. To solve this problem you should replace your original video cable with a RGB cable.... 

REPAIR

None Joypad works on the console.
Very often you got this problem when some fuses goes burned. Use a Multimeter to find burned fuses. Replace it with one of the same value. A set of fuses is available as replacement parts.

Memory card is insert, but i cannot read or write data
Same problem as above, also together.

One or more buttons on joypad don't works.
Try to clean well the pad inside. To open the pad use a small screwdriver, keep track of where the screws, cables and internal components go as the pad is disassembled. Use alcohol and soft bush to clean.