i changed the red led, and added 2 SPDT switches...1 for the region and 1 for the 50/60Hz...when the 50/60Hz switch is set to 50Hz (GND) my tv flickers constantly of the screen of the game sort of up/down...did i do something wrong or is it just my tv? What games could i use to determine if the region switch worked...i have tried a few games and i cant tell any difference.
Your TV flickers and rolls because it can't handle 50Hz. That' pretty normal.
As for test carts... I know ThunderForce IV did a region check. So did Mega Turrican.
I think its pretty neat he did a mod without knowing what it does. That's ok man at least you got a cool switch!
You will only need to start out in 50Hz in order to run region protected PAL games (as a rule of thumb, all games released in 1993 and later have this type of protection), you can switch over to 60Hz as soon as the title screen appears.