Sony (Trinitron)KV-32V40 (manu. 1998)

The problem that i am experiencing is when the set is turned on it blinks constantly non-stop the entire time the set is on ,it does it while watching dvd's and playing playstation and of course when the cable box is on.When the problem began which was about a month ago it would only blink for the first 5-10 minutes then it would operate like it should Please Help!!!