> Did it ever work or did you just get the unit and it's always been like that? If it's always been like that it sounds like a power problem. I know you said you had a 12V adapter which probably should work although it makes the regulater work harder inside the unit. If you get it to work I'd suggest switching to a 9V adapter. You didn't say whether you had an AC or DC output from the adapter. DC is preferred(required?). If it's DC it must be center negative. If you have center positive then your adapter is not powering the GD at all and this could be causing your problem. Take a meter and check the voltage on the adapter.
> Can you press the right controller button on power-up and get to the GD screen?