TV Repair Tips V LCD TV Repair Tips & Case Histories LCD/LED & 3D TV Recommended Troubleshooting & Repairing Guide: V –LED & LCD TV. This is a copyrighted material; no part of this guide may be reproduced or transmitted in any form whatsoever, electronic, or mechanical, including photocopying. Download LCD MONITOR REPAIR GUIDE service manual & repair info for electronics experts.

Lcd Monitor Repair Guide Pdf

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Download LCD MONITOR REPAIR GUIDE JESTINE YONG service manual & repair info for electronics experts. This is a copyrighted material; no part of this guide may be reproduced or transmitted in How to Repair LCD Monitor Power Adapter How to Repair No Voltage test. The third. No much lcd monitor repair book or Lcd Monitor Repair Pdf has compiled these questions. 1) how repair lcd monitor with no power problem, 2) how trouble.

LCD Monitor Repair

Please tick the box below to get download link: If you have any question about repairing write your question to the Message board. For this no need registration. If you are not familiar with electronics, do not attempt to repair! You could suffer a fatal electrical shock! Instead, contact your nearest service center! To open downloaded files you need acrobat reader or similar pdf reader program.

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First off, let me say, great site! Without it, I wouldn't have been able to even begin diagnosing my monitor, I found the service manual for it here. Hope to be coming back many times in the future! I was using it a while back, and then it just turned off.

I got the resistance value changed to K ohms each resistors and the diode is ok. According to Ohm law, the resistance that increases will result the voltage drop. I have the spare resistors and replace the resistors in same specification properly.

Lcd Monitor Repair PDF

Within my expectation, the LCD monitor now is returned to normal condition. I leave it run for few hours. Finally, I call the customer to collect the monitor next morning. He receives the monitor happily and gives his appreciation to me. The whole process of the testing and replacement is only taking 1 hour approximately.

I can earn dollar in the short period based on my experience and good knowledge of the working principle on LCD monitors. Now, you can grab this opportunity to learn the systematical method from this book which compiles a step-by-step and headto-toe practical guidance in photos for smps repairing of LCD monitors.

You too can become a professional repairer and earn lots of money from this kind of repair. The answer is always yes with you invest your time and energy to learn the knowledge of basic electronic component testing and learn the working principle of the lcd monitor circuits and stay focus in Lcd monitor repairing. Always remember your safety first. To become a successful lcd monitor repairer, you must study the knowledge of the electronic component testing and its characteristic such as various type of fuses, resistors, capacitors, inductors, diodes, transistors, integrated circuits and etc.

This is a very important step to analyze which electronic components incurred in the lcd monitor fault. The wrong analysis of the electronic component testing will waste your time and energy.

But, prior to testing the electronic components, you must know the basic electronic component coding which is an essential and initial part for the correct interpretation of measurement and testing on Lcd monitor circuits.

SMD Resistors are usually coded with a numerical equivalent of the familiar three band color code.

The first two or 3 digits are the first two or 3 digits of the resistance in ohms, the third or 4th is the number of zeros to follow the multiplier.

Resistances of less than 10 ohms have a R to indicate the position of the decimal point. SMD ceramic capacitors are sometimes marked with a code, consisting of one or two letters and a digit.

The first letter if present is a manufacturer code i. For example S3 is a 4. For SMD electrolytic capacitors are often marked with their capacitance and working voltage, e. Sometimes a code is used instead, which normally consists of a letter and 3 digits. The letter indicates the working voltage and the 3 digits 2 digits and multiplier give the capacitance in pF. Below example of SMD Capacitors will make this clearer.

The band or stripe indicates the positive terminal. For example, a capacitor marked A is a 4. The purpose of the analog circuits in the inverter is to transform a DC voltage input into an AC voltage at the output.

The inverter is linked to a lamp circuit consisting of a fluorescent lamp, a potentiometer, a current sense resistor and a rectifier diode terminal of the potentiometer is connected to the inverter controller, which is also part of the lamp circuit. In the design of Royer regulator, the lamp ballast capacitor is usually in the range of 12 to 22 pico Farad in order to drop excess transformer output voltage after the lamp has ignited.

A micro-controller Unit MCU will carry out the control of the lamps.

The MCU allows the same inverter circuit to drive multiple lamps while each lamp with the individual dimming control is reserved. The result is creating an unity lamp brightness for systems such as LCD displays that require multiple lamps and where all lamps must produce the same level of intensity. The inverter controller receives the current sense and dimming input signals and generates an appropriate output for the inverter to produce the required AC voltage needed to drive the lamp.

For the backlight inverter board with Direct Drives, the main advantages of the pushpull transformer are its dual primary winding construction which the voltage impressed across the primary in Direct Drive modules which are twice the supply voltage.

Direct Drive topology also enables efficient inverters that can run directly from 3. This is equivalent to a 4 transistor full or H-bridge drive configuration and makes for very efficient operation at low voltages.

Unlike the implementation of Royer regulator, new approach of Direct Drive for lamp strike voltage generation relieves the transformer from operating continuously at full lamp strike voltage once the lamp is ignited. Direct Drive transformers will optimize for normal operation where they spend most of their life.

Small transformers can be used while system a CCFL is only present for the instant it is required. Gradually destroying the insulation material, high voltage corona discharge can be more easily avoided with Direct Drive designs. With the new transformers and IC controller, the backlight inverter board of Direct Drive has been developed completely which the first two are 6 watt units that can drive lamps having strike voltages of up to Vrms.

A two lamp magnetic now in development will support up to Vrms strike and 12W operating power. Clearly, strike capability is enhanced while transformer size and reliability are improved.

In big picture, Direct Drive designs reduce transformer output voltage after ignition, permitting ballast capacitance values to be much larger. Now you have learned the direct drives backlight inverter board. You will be more familiar with the inverter board when you have chances to open out the LCD monitors casing and observe it yourself. Inverters must accept the dc input voltages, typically 12V, and provide ac outputs of to V to run the lamps.

To ignite CCFL lamps, these circuits must supply short strike voltages that typically are double that of their working voltages.

Numerous applications also expect efficient dimming capabilities to let lamp output to match surrounding light conditions and so extend the lifetime of lamp. It depends on the number of ccfls are used, inverter circuits combine with single, dual or quad high voltage transformer to generate the high voltage required for ccfls.

For ccfl inverter voltage generation, the inverter circuit with the buck regulator consists of two power semiconductors, one power inductor, a PWM regulator IC, and a high current capacitor. It provides a healthy secondary power source from the primary power source.

The Royer oscillator consists of two transistors, a high-current resonance capacitor, a high-voltage transformer, and a ballast capacitor in series with the lamp. It provides an alternating current source to drive the lamp. The current amplitude is controlled by the ballast capacitor through the lamps negative impedance which dropping an approximately equal voltage across its positive impedance.

In theory, the lamp current will be the total transformer output voltage minus the lamp voltage lamp voltage is inversely proportional to current divided by the capacitors impedance.

The total power and the required strike voltage will limit the minimum size of this transformer. Because it must operate at twice the normal lamp running voltage all the time, its size must support full strike power and voltage, even after the lamp is ignited. Knowing the good ccfl inverter voltage is critical to troubleshooting LCD Monitor.

You can use the spare backlight from another working LCD Monitor. This is important method to test the backlight. Otherwise, you will waste time and money if the fault is on the inverter circuit or dry soldering and etc. Normally, the backlight fault will be suspected when you found the display is flickering or discoloring. Double check any dark end on cold cathode tube.

Replace new tube if you discover the dark end of lamp tube. To replace the backlight successfully, you must pull out the backlight gently together with its casing.

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Some backlight can be easily removed while some were tough. For totally sealed type backlight, you must be careful when removing the backlight.

Once you tear off the backlights tape automatic bonding accidentally, the panel of LCD monitor is damaged and no longer operate in good condition. Always bear in mind, the tape automatic bonding is very fragile before you pull out the cold cathode tube. Be careful and good luck for your lcd monitor backlight replacement.Lcd monitorbol kijelzot laptopba.

That means your clearest view of the display will be to look at it straight on. However, if you dont understand the function of circuit boards, you will waste time and energy to fault finding on lcd monitor. Inverter generates from up to plus VAC from one, two or even four high voltage transformer depending on how many backlights were used.

This is a very important step to analyze which electronic components incurred in the lcd monitor fault. Some technologies boast the ability to dynamically control contrast and offer contrast ratios of and above! In some LCD Monitors, you can use both of your hands to gently but with a little bit of pressure to remove the side cover.

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