TCL color TV screen only blue green color alone lacks red strange fault sharing - android - Phones Developers

0805 side blue

These days, the South China’s Shantou’s misty rain is a bit like “West Lake March Day”, and the temperature is between 12 and 18 °C. The drizzle in the wind blows all kinds of flowers and plants outside the window, as if Play a beautiful symphony. A cup of thick Kung Fu tea is accompanied by a friend's sea otter, and the mood is exceptionally comfortable.
The phone rings, the cosmetics company CEO calls, the home color TV is broken, this is the mental support of his father, please go to get it.
According to the appointment, the 34" TCL high-definition machine is playing something, the picture is only blue-green color, the red is lacking, the red picture is only purple, the sound is normal. The boss said that I rarely repair the electric appliance now, I did not dare to ask me. Just invited two maintenance masters outside, all of them are the same - "Like the ancients"! Originally he wanted to change the LCD, but his father said that the LCD is not good, the image is not bright, Yao Ming is a dwarf, etc., or hope to put He believes that the "color is very good" color TV repair, look at the habits. And the boss also knows a little about electrical common sense, this color TV is still less than five years without a reason to sacrifice.
Disassemble the TV and detect the three-color output. The R output is 175V and the G output is 152V. The B output is basically the same as G. Check the RGB excitation again, and the balance is about 2.3V. It should not be the color difference output cutoff, and the fault is locked on the output board.
Fine analysis: If the R output is cut off, the voltage should be 200V, and the actual measurement is 175V. The voltage is relatively high. Is the emission capability reduced? We all know that the voltage is inversely proportional to the current. Since the R output will not be cut off, it can only be explained as the R gun's emission capability has dropped. But his father said that a few days ago, it was the same every day.
In my experience, Xiang Guan is also no reason to "dead" overnight, just like a cordless telephone transformer in the boss's home, 7.5V is just right, three guns are detected, basically the same, so the elephant is still "young and promising ".
Replace the output IC, detect each related bypass, clamp the circuit including ABl, etc., no abnormalities are found! This is really "ancient and wonderful." Hahaha, I have been immersed in the maintenance industry for more than 20 years. With my rich experience, can you stump me?
Smoking, drinking tea, a smile at the corner of the mouth - high-definition machine tube due to the internal speciality, often the tube seat will also cause strange and strange faults! At this point, the tube seat is removed: the drop of the sky, the connection of FOUS2 has been broken! Decisive replacement, the image is gorgeous. The boss’s father smiled and saw that his teeth were not visible. The Chinese cigarette was an unfinished one. Say to his son: Take a look, or this TV is good. The boss is speechless...
The machine is repaired, and the words of praise can't be heard. However, there is a problem that needs to be discussed with the forum experts:
FOUS2 (Focus 2) loses voltage. Why does R output current drop and G and B are normal? I hope that the masters are educated! Tips: Due to the special nature of the high-definition video tube, some faults are different from the old CRT tube. Therefore, when the normal and strange phenomena of the circuits are still there, sometimes considering the tube seat will have a multiplier effect!