Phillips magnavox 27 inch tube tv had white lines going through it can hear sound then turns off

SOURCE: POWERS DOWN AFTER 4 SEC

crt beam current too high causing shutdown as you know. Check cathode voltage of each cathode, normal levels depend on picture is around 130-150V. Missing 200V to crt board. Screen voltage problem normal 300-500V. Flyback or bad crt. ABL circuit problem. Jungle IC.

SOURCE: Horizontal line in the middle of the television

tnewk, Your symptom is no vertical deflection = check for
B+ voltage present at vertical output IC.If present = replace IC.
If missing, check B+ power supply............T.

Note: 10 ohm resistor replacement symptom = No video,
lit white screen with retrace lines ...........T.

SOURCE: screen is black

on that tv you have to check just for circuit of high voltage - check
transistor near flyback transformer - delfo

SOURCE: TV BLACK SCREEN WITH THE POWER ON.

It needs repair.
If the line is vertical, then something is damaged on its horizontal circuit section on the mainboard.
If the line is horizontal, the vertical circuit section is damaged.
have it repaired to a qualified service center or person!
avoid switching it to avoid further damage on other parts!

SOURCE: MAGNAVOX 27" TV, PICTURE START UP PROBLEM

This problem with your television set is more than likely a problem with intermittent component failure. The fact that the television turn on for awhile is a sign the the component or components are intermittent.The reason the television turns off is that it goes into the protection mode caused by the intermittent component or components. They are unstable and are causing unstable voltages supplies to appear in the circuits. The television has a built in feedback circuit that will detect the faulty operation and turn off the television. When it stabilizes again the television turn back on. This is usually a sign of aging or faulty components. The problem will only get worse and the television should be thoroughly tested. You can call Magnavox customer support at this telephone number 1-800-705-200. Give them the model number of your television and tell them about the problem you are having with intermittent turn on of the television. They will be able to tell you where to take the television for testing and service. I hope this information helps you with your problem.