How to reset display settings?

[mikezang]

My Sharp TV only support 1080i, so I use a DVI-DVI cable to connect a monitor, then use Mini DisplayPort to HDMI adapter connect Sharp TV.

Then boot Mac mini, I got Open Screen on Monitor, and I set HDMI adapter to 1080i, then I power off and unplug DVI cable and boot again.

Well, I got what I want on Sharp TV, it is 1080i, but I found a 720p, I selected it, now the TV becomes to black screen with "Invalid video signal"!

I reconnect monitor, so Sharp TV is ok, but if I unconnect monitor, the sharp TV will be black screen.

I thought it might be some display settings are saved, because it was good when I first use TV after set to 1080i, but I selected 720p that is PAL TV, not for mine NTSC TV, after that selected, THe sharp TV can't be used alone, how can I reset display settings? what can I do for this case?

Please help me, GOD!

 

[666sheep]

Zap PRAM. It should reset video settings to default.

 

[reggievee]

I think I did something very similar.

I set up my Mac Mini to my Samsung 40" LCD using the Kanex cable to go from MDP to an HDMI cable.

Everything was going swimmingly until I goofed it all up. As I was playing around I accidentally selected 1080p PAL rather than just 1080p (from the display drop down). Now I just have a black screen with a "Mode Not Supported" message. I can't see anything on the screen to be able to reset the display setting.

I have an appointment at the Genius Bar tomorrow to reset my Mac Mini, but wondered if anyone had any tips to try to do this from home. Would love to be able to get this going tonight.

I'm using an Apple brand wireless keyboard and wireless mouse.

Have tried hard reboots, doing the PRAM ZAP and Command F2.

Any assistance is appreciated.