My hp vs19e monitor has dark screen and blinking power button.

my monitor powers on with a dark screen for first two minutes then comes on with no problem. when left off for more than 5 hrs. It repeats the same problem. the problem has esculated with screen remaining black for the first 2 to 4 hrs. of being turned on before showing. I was told by a monitor repairman that the problem is with the power module and it can be repaired with a estimate of 156.00.