I have a viewsonic A90f+ monitor, that worked without any problems until one day I went to turn it on and nothing happened. No amber light, nothing. I plugged it into a seperate outlet and nothing. I unplugged it and let it sit for 2 weeks. I then attempted to plug it back in and still nothing. I changed the power cord and nothing. My brother used his computer tower and attached the monitor to it and now it will turn on for 4-5secs and click off then back on. The green light comes off and on, but the amber light will not come on. When the monitor switches on the picture is beautiful on it.

What can be the problem and is it worth taking it to a repair shop to be fixed?
Due to Viewsonic's policy, I found that my supposed 3year warrenty with them was only a 1 yr warrenty because I bought my monitor on April 1st, 2003 instead of March 31, 2003.

I had the same problem(cycling on and off), after replacing horizontal deflection transistor it was good. The difference between your and brother's computer maybe because of different horizontal frequency (=different resolution or/and refresh rate).