I'm having some problems with my DS's bottom screen. It seems that its refresh rate got lower, I can see dark lines moving on it. The top screen seems fine. When I tap hard on the back of my DS, it seems to get worse, though, but one time it got fixed somehow. If I take it apart and fiddle with contacts, will it get any better? I'm waiting for a housing shell, so I'm gonna take it apart anyway, won't want to waste that chance.