Hi to everybody. Due to the problem of "overbright" screen on my Sony CDP-E500 Trinitron monitor (21"), I inform that I have solved the problem using the WINDAS software and a simple RS232-TTL cable. The valour of "G2" was 160, with 600V measured between ground and G2 point. I have set up the G2 valour to 122, obtaining the correct valour of 514V (Sony specs for my model: 512v). Now I'm trying to understand the other features of the program, to set up my monitor perfectly.
Thanks to everyone that helped me to solve this problem!