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TCL is the old brand of television production, but it also inevitably encountered a lot of problems. Many times, users do not know how to do it. Today, Xiao Bian has compiled several common types of faults for common models of TCL LCD TVs for everyone, hoping to help everyone.
Model:LCD20A71
Fault phenomenon: black screen
Analysis and Maintenance: Booting sound with no image The black screen backlight can be lit without the screen display, and the detection power supply is all normal. With an oscilloscope, the TFT has a signal output, which proves that the screen may be broken. After the screen is opened, it is found that the screen power supply insurance F501 is bad, and the fault is eliminated after being short-circuited.
Model: L32E77
Symptoms: The light does not turn on
Analysis and Maintenance: According to the fault phenomenon, first detect the 5V standby power circuit, and find that the output voltage only jitters between 3-4V. Suspect the IC1 there is a problem. Replace it. If the power failure is found, check the circuit. The power supply output is low, only about 3 volts, the normal voltage should be at 16 volts. When checking the relevant components, the DB1033 volt regulator is returned to normal. After the replacement, the voltage returns to normal and the fault is eliminated.
Model: LCD1526A
Symptoms: There is no sound
Analysis and maintenance: boot image is normal, no sound, check the sound system is set to DK state, measurement U8, U19 working voltage is normal, the bus voltage and waveform are normal, suspect U7 data problems, U7 after the test sound map is normal.
Model: LCD47K73
Symptom: There is no image with sound
Analysis and overhaul: Turn on the power and the screen will be dark. Disassemble the machine, measure the working voltage of the backlight board, and the switching voltage is normal. This phenomenon is generally a problem with the backlight board. After applying for the replacement of the backlight board, the machine is normal.
Model:LCD40B66-P
Symptom: There is no image with sound (dark light)
Analysis and Maintenance: Turned on for a while, there is no sound, but there are dark lights, there is light that the backlight board is good, doubt the motherboard and the central control board problems, test screen working conditions, the voltage of each foot is normal, so Change center control board, troubleshooting.
Model:LCD40A71-P
Failure phenomenon: Do not boot
Analysis and maintenance: after the boot can not hear the relay pull, measured after the power output is normal, the normal working condition of the relay after the replacement of the relay troubleshooting.
Model: LCD26B66 (GN21 Series)
Symptom: No image on boot
Analysis and Maintenance: After power-on, no image was found, press the menu button to search for the station, but the remote control was found to have no effect. Suspected memory IC problems, re-copy software, found that the fault remains the same, and then re-copy FLASH after the fault is the same, and finally found that every time you boot, there will be a Nike symbol at the station logo, the analysis may be a problem with the Nisin version, Finally, it was found that the L504 IC's L504 circuit was open and the fault was eliminated after replacement.
Model: L42M61R (MS88B movement)
Symptom: No sound when cold boot
Analysis and Maintenance: The power supply voltage of the boot test U27 (TSA7266) is normal, and the mute circuit is working properly. The fault is not in the amplifier circuit, careful analysis of drawings, in front of the U27 there is an integrated circuit U38 (TDA1308) dual channel amplifier, generally used for headphone efficacy. Check the working status of U38 and found that the power supply of the 8-pin is only +3.5V and normal is +5V. Check the +5V power supply circuit U41 (MP9583DS) and found that one pin was falsely welded and the welding machine was tested and troubleshooting was done.
Model: L42H78F
Fault phenomenon: dark picture
Analysis and maintenance: boot with a different signal test machine, found only in the TV state, the grating is very dark, the other few are normal, the first replacement of high frequency motherboard failure remains, measuring the power bus voltage is normal, then think of software After the hardware repair method, try substitution 24C64, troubleshooting.
Model: L19E72(MS18A)
Failure phenomenon: irregular image drawing and moving down
Analysis and Maintenance: When the fault occurs, this motherboard will disappear when the main board is faulty, and the main board fault will not appear after the fault is normal. However, after a certain period of time, the fault will occur again. The analysis should be caused by the original plate off the original welding artifacts, after the U100 (MST718BU) and the external exhaust resistance repair welding fault persists, and then in the event of failure, measuring the motherboard to the central control board LVDS cable socket S103 foot voltage, in When the voltage was measured at 229 feet, it was sometimes not. When the voltage was normal around 1.4V, the image returned to normal, indicating that the line was in poor contact. After the 29-pin connection was re-welded, the fault was removed.
Tags: Smart TV Communication, Smart TV Forum
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