TV model: TCL LCD TV L24E09
Symptom: The screen turns on but shows a gray image, while the sound and other functions are normal.
Analysis and overhaul: This is a 24-inch LCD TV with a gray screen issue, but the audio and operation functions are working properly. Based on the symptoms, the power supply and backlight system are functioning normally, so the problem likely lies in the display panel or the logic board. After disassembling the unit, I checked the LVDS output from the motherboard and confirmed that the screen’s 5V power supply and signal voltage were within normal ranges. This indicated that the motherboard was operating correctly, and the fault was most likely in the screen component (which includes the logic board and the panel).
After removing the dust cover, I identified the logic board model as M236H1-L01-X+G. During a power-on test, I measured the PANEL VCC at 5.28V and VAA at 13V. When testing the input pin of U1 (A1AOC25 LDO), it read 5.28V, but the output was only 0.56V. After turning off the power, I checked the ground resistance at the output terminal and found no short circuit, which suggested that the LVDS signal receiver and timing control chip CM2713A were functioning normally. Therefore, I concluded that U1 (A1AOC25) was faulty.
I looked up the specifications for A1AOC25 and tried to determine its output voltage. After testing, I confirmed that U1 outputs 3.3V via V33V. I replaced the faulty U1 with a 1117-33 regulator. The repair was successful, and the TV returned to normal operation.
TV model
U1 input voltage value
U1 output voltage value at fault
Picture of faulty component U1
Replace the picture after U1
Picture after the TV is normal
Solar Battery,Wall-Mounted Energy Storage Lithium Battery,Lithium Iron Phosphate,Stackable Lithium Battery
JIANGSU BEST ENERGY CO.,LTD , https://www.bestenergy-group.com