I have a CRT TV of the brand Gradiente model GT-2825 that the fuse F902 of 2A has opened. Replace fuse. When I turned on the TV I noticed that the screen is all white and with normal sound. In my city it is necessary to use a digital converter to get the image of the local station's programming.
The measured RGB output voltages are 100v, 60v, 60v on the RGB guns. The regulation of the of screen of flyback is almost at the minimum.
The ideal would be to be able to test the main voltages of the tv board without it being connected to the tube, is it possible?
Sometimes I use the TV board and more the baffle.

When the TV screen becomes white and the reverse lines are visible, then first of all you need to check the power supply voltage of the video amplifier board.
Check 12V, 196V, signals R-Y, B-Y, G-Y, Y , SCREEN and HEATER.
If the voltage of 12V, 196V or SCREEN is underestimated, then there must be a malfunction.
I also advise you to check all the voltage at the output of the power supply and if they are lowered, then the electrolytic capacitors are most likely defective.
If you need a scheme, I can send it to the e-mail.

Good luck!

Hi friend, can you send the electric scheme of the tv by email? My email is: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.
I will be very grateful for the help

eletmoraes пишет:

sent

checked the voltage between pin 1 and pin 4 of the STR30130 -> 131V
checked for voltage on capacitor C536 (10uF / 250) -> 186V
Checking the voltage at the vertical output IC421 -> ok
I used a DVD player (player) in the audio and video input -> no picture with white screen.

Note: the flyback screen potentiometer setting is at minimum.
Image obtained according to the attached image

Although the voltage on the capacitor C536 of 10uF / 250v is 186V when the tube is not connected I am getting over the transistors RGB voltages of 35v on a transistor and 22v on the other transistors of RGB output (with the tube connected on the kinescope board)

Check the voltage of the accelerating electrode (screen) CRT.

Connect the kinescope board and measure all voltages and write.

I did the same test without the kinescope plate being connected to the tube and the voltages remain the same, ie with the kinescope plate placed or not the voltages remain the same.

I wanted to see if the problem could not be the potentiometer of the screen that is inside the flyback can not be defective?