Amstrad GX4000 blank screen

[phreak97]

I picked up a gx4000 while in london a few weeks ago, just got a game for it yesterday and all I'm getting is a black screen. Interestingly when I use rf I get a black screen even when the console is off, not static. Might be a feature of the console though.
When I turn the system on the screen flashes like normal but thats all.

The crystal is outputting the correct frequency..

Oh and the 7805 regulator is getting very hot, so im thinking something may have gone short or low resistance.
Are there any common failures?