Picture does not always come on, sound always comes on, when TV is turned on; some times takes as many as 5 cycles to get picture to activate.

Try another lamp. Error 5 is Lamp power supply, but its usually always the lamp bad.

This problems the FBT-the Flyback Transformer have cold solders.Must resolders the FBT.The right side wall of the FBT-the "H" horizontal transistor,must be also resolder too.

Model number and brand info of tv are always very helpful to recognize what tv you have and that gives an idea about possible cause of problem.
Without above info, no one can guess about solution.

Replace the lamp.

check the oscillator

There is possibly a loose solder joint in the horizontal drive circuit. There is a little coupling coil just before the horizontal output that will get loose. This should not be real expensive to have repaired.

the service light is blinking because you in fact need a new bulb also is why u have no picture

may be bad cap take to tv shop good luck
have to have esr meter to check

IT GAVE OUT A LOUD BANG AND NOW I HAVE NO PICTURE OR... Mosfet Transistor blow out.  Transistor K3316 or replace the Power unit supply. This problem was caused by a low power voltage. SONY SONY KE-42TS2U

It's simple. Your TV does not like you. Perhaps you need to speak kindly to it before you force it to watch BBC for hours. Buy it a scone.