I. Reasons for opening the ash screen of the tcl lcd tv
One, the signal lights are on, but unstable, indicating that 5v is abnormal, that the measured 5v voltage is around 3v and unstable, and then the inspection of the perimeter of ic12 and feedback steady voltage circuits is started. After examination and no abnormality was detected, the failure of ic12 was changed, and the total output of the waiting circuits was 2 and the group of 5vs was 30vs, so the 30v output was broken and the return to normal was 30vs, and the route was broken, the measured d30 was softly punctured, and the lcd television failure was removed。
When the light is turned on, it is suspected that the problem is on-line circuits or at the front level. Measurements of the capacitation of 300v also have a voltage of around 300v, indicating that the pfc circuit is not working. There's no power supply from 5v and pfc
There was no abnormality in the voltage, no problem with the replacement of ic, no problem with r96 and q13, and it was not intended to be detected that d23 had been punctured and that lcd television was returned to normal。
Ii. Functions in the liquipment of ttl light-crystal tv once
The main panel is replaced。
2. Lcd logic panel failure。
3. The problem of lcd-tv connections does not occur in the case of hdmi interfaces. If the av signal input looks red and white and three-coloured, it can either be replugged or cleaned up. If the mass interface enters y, pr, pb, notes the corresponding colour, and the other two audio lines are not plugged in, this is the area most prone to ash screen phenomena。
Iii. Methodolization of ttl liquid-crystal tv obligations
Turns on the back, insides, four separate panels, general power panels, the v59 formula master panel, high-pressure backlight panels and independent logical panels. Ash screen failure is probably the problem with the screen. First check the logical panel, 12 volts of power, a low-pressure spread, normal and steady input of 3. 3 volts to output 1. 8 volts
On the other end of the logic board, there's two big stickers with signs of being removed
There is also a multi-capacitation and filtration wave, with no voltage and short circuits, with two patches removed and two patches replaced, and a 2. 2uf, 50v electrolytic cap, test-opening, two maintenance positions, 15 v and 25 v, respectively, and failure resolution。
