Hello my name is ***** ***** I am. Yamaha certified technician. I see your having a problem with your DGX530. When it does come on and you have sound can you tell what sound it is? for example a piano or guitar?
Take a look at the rear of the unit on the left side there should be a control marked contrast. turn it and see if any change in the display happens.
Hello I wanted to check and see if you had the problem corrected or do you need more help?