Introduction to LCD TV Repair
This month article is about the basic LCD TV repair. I do get emails from beginners asking about
how to understand and troubleshoot LCD TVs. Although this is not a complete article about LCD TV repair, I
believe this article in some ways could help them in understanding the main function of the important boards
found in LCD TVs. Let’s start.
A- Power Board
B- T-con Board
C- EMI Filter board (In other designs this board is built into the Power Board)
D- Inverter Board (In some designs this board is built into the Power board and is called as I/P
board)
E- MainBoard
F- Jackpack
G- Side Key Panel/Power Control/Remote Receiver Unit (IR/LED control)
H- Left Speaker
I- Right Speaker
J- LCD panel
K- LVDS cable
The function Of LCD TV section
Power Board
The
Power Supply Board is usually the biggest and heaviest board found inside the LCD TV. Some repair techs call
power supply board as “Power Supply Unit” and “Power Supply Module” or just “PSU”. It converts the main AC supply into DC voltages that can be used by the circuit within the LCD TV.
Sometimes the power board is joined together with inverter board and is called as I/P
board.
Common faults- No power, low power, power blink and intermittent no power.
Timing Controller Board (T-con board)
The T-Con Board is the smallest board
found inside LCD TV and is usually only found in LCD TV's. The
function of T-con board is to control logic signal of gate and source for driving TFT LCD. The T-Con Board is
sometimes referred to other names, such as "Controller Board," or "Control Board."
A Typical T-con Circuit Board
Common faults- White Display, No display, Double image, Display distortion (black and white vertical bars on
the screen). Multiple vertical/horizontal lines across the screen.
Inverter board
The
inverter boards are usually found along the edges nearest to the TV Panel and are only found in LCD's. These
boards function is to convert the low voltage DC supplied (12V or 24 V) by the SMPS into a high AC voltage (500
to 1500 Vrms) to light up the backlights. These boards can be found as a single board or built in with the power
board called as I/P board.
Common faults- Display shutdown after few seconds, Dim display
Mainboard
The simplest way to
identify the Main Board is to look for the circuit board with the audio and video inputs and
outputs.Sometimes the Mainboard is called as Motherboard, Main Unit, Digital board, Scaler board, A/V
board, Main Module, Logic board or even A/D board. The function is to take in the video and audio signals and
convert the analog video signals into digital signals that can be sent by the LVDS IC (low voltage
differential signaling) to the T-con board.
Note: Sometimes the audio section/RF Input/ Rear Inputs is separated from the
mainboard.
Common faults- No display, no color, screen full of vertical lines after sometimes, no sound, horizontal
lines and block, sometimes the LCD TV fault (usually display problem) can be due to software problem where
you need to update the software.
Jackpack Section
The audio signal is taken to the audio processor and then audio amplifier which then drive the
left and right speakers.
Note: Sometimes the audio section/RF Input/Rear Inputs is separated from the mainboard (as
seen from the above photo) and is called as Jackpack or Signals receiving board.
Common faults- No sound, distorted sound, High Pitched whine, no TV reception, unable to tune to certain
blocks of channels, channels change randomly.
Below is the all in one Mainboard (Key Panel, Audio, RF input, Rear Inputs, Ram and Main
MCU.
LCD Panel
LCD stands for
liquid crystal display(LCD
) and it is a thin, flat electronic visual display that uses the light modulating properties of liquid crystals
(LCs). LCs do not emit light directly thus backlights are needed to make these LCD displays
visible.
Common Faults- Vertical/horizontal thin line/s or bar, white display, garbage display.
Backlights (Lamps)
The function of backlights (CCFL or EEFL) is to
illuminate the LCD from the back of the display panel.
Common faults-Display shutdown after few seconds and display flickering
You can test the backlight by visiting my blog at :
http://www.jestineyong.com/review-of-the-blue-ccfl-tester/
Hope this article is useful to those who wish to enter the field of LCD TVs repair.
Recommended Ebooks:
Click here to learn LCD TV Repair Secrets By
Damon
Click here to read the review of LCD TV Repair Tips
Volume 2 by Kent Liew
Click here to learn how
you can become a Professional in Switch Mode Power Supply
Repair
Click Here To Learn DVD Player Repair
By Humphrey
Click Here To Learn How To Repair LCD Monitors With the
Help Of 10 True Repair Case Histories
Click Here To Learn LCD TV Repair Tips Volume 1 by Kent
Liew
Click Here To Learn Laptop Motherboard Repair
Click here to learn how
you can become a Professional in Testing Electronic
Components
Click here to learn how
you can find burnt resistor value
Click here to Get 24 Best Electronics Repair
Articles
Click here to learn how you can become a Professional in
LCD Monitor
Repair
Click here to learn how to repair Plasma Television By
Damon
Recommended Basic Electronics
ebook By Greg S
Carpenter
Recommended Mr Steve
Cherubino Laptop Repair Videos For
Beginners!
Recommended Mr Kent LCD TV Repair Membership website-Visit
Now!
Recommended Mr Kent
Plasma TV Repair Membership website-Visit Now!
Recommended Print Head Repair Guide By William
Hor
Recommended Mr Kent Projection Television Repair Membership website-Visit
Now!
Recommended CRT TV Repair ebook by Humphrey
Kimathi
Recommended Computer Repair
Course
Automobile Electronics
Repair
Basic LaserJet Printer
Repair
Mobile Phone
Repair
Click Here To Learn LCD TV
Repair
Click here to learn LCD TV
Repair Case
Histories
Click here to learn PS3
repair
|