Once again after a long time I get a feeling that I am an engineer. I had posted about my problems with my Sony monitor earlier. Today I went to a few shops trying to get a couple of components for the monitor to change. I had to walk for about an hour and a half to go through those shops (this doesn't include the time to travel to that area from home). But patience paid and I finally got the capacitors and resistance for the monitor.
Opening the Sony monitor was a difficult process but if you do it step-by-step with some patience you do get to learn a lot. It took us around an hour and a half to dismantle it completely. See the D-board for it above. Changed the capacitor which looked faulty and built the monitor again. Connected power supply to it and carefully switched it ON. Walla! High-pitched noise is almost gone. Whatever is left was only heard for the first minute and has not come back again.
The monitor is working perfectly now although I think I might have to change a couple of more components. But I can't complain, the engineer did such a nice job!