help with some external screen config with my powerbook g4

ok so long story short i have a 17" powerbook g4 that is hooked up to an external display and it works just fine expect one thing......... the display itself is having issues and for the first 5 or so minutes the screen flashes and i think this i due to a bad capacitor. but if there is some way in which i can put the powerbook to sleep and keep a screen saver running on the external screen so it would have continuous power to it. if this cant be achieved i might just see if i can get the g4 to go into the screen saver and have it displayed on the other screen.

if you can help i would really appreciate it, but i still need to check out the capacitors

Thanks ahead of time,
Boneskid1

i dont want to run it in clam shell because i want both screens
i will try the sleep suggestion