LCD Monitor Repair

Repairing the DELL E153Fpc LCD Monitor with the complaint of display shutdown after few seconds (power LED still on) was not difficult. Normally when this type of problem happens, we would first suspect the inverter board, then the filter capacitors and lastly the main board. A defective in one of the lamps and a faulty TL1451AC PWM IC or inverter ic may caused the display to shutdown as well. If the lamp is defective, it will send a feedback to pin 3 or 14 of TL1451AC IC and caused it to stop producing output signal thus the display just shut off once you switch it on. The power board is using a SG6841D pwm ic and a FQPF7N80 power fet . If this power section blow, it is quite easy to troubleshoot because it has fewer components. You can also use other part numbers to substitute the power fet.

As usual, after opening up the cover, I would first check for any burnt components, loose connector, cracked board, dry joints and etc before doing the voltage test. As for the lamps, I would check it last because lamps were seldom spoilt. Upon scanning for any bad components before starting the voltage test, I found a filter capacitor that had turned into darker color. Using the ESR meter revealed the ESR ohm has shoot up to 12 ohms. This filter capacitor located at C922 with the value of 1000 micro farad 16 volt. If you don’t have the ESR meter you can always use the digital capacitance meter. The value that I got from measuring the bad capacitor was 57 microfarad. If you don’t have ESR meter, make sure you get one-it’s fast and accurate.

Now, the question is why a filter capacitor can cause the display to shutdown? If you carefully see the picture, I’ve drawn the yellow path to show you how the voltage is flowing. By the way, the voltage at the bad filter capacitor line is 12 volt. The voltage passed through a SMD transistor in the start circuit and flow straight to pin 9 (VCC) of TL1451AC IC. In order to let the 12 volt to flow through the transistor and reach the vcc pin of the ic, first, a ‘on’ signal must be sent from the main board to trigger the transistor. If no signal send to the transistors (off signal), both transistors can’t be turned on and no voltage will follow through the ic. Thus if the main board or any of the start circuit components spoilt, there will be power but no display because the TL1451AC would not send signal to the Royer type L, C resonant and boost circuit, so no high voltage produced by the high voltage transformer and this will lead to no display.

In the above case, the LCD Monitor display shutdown was due to the ripple because of the bad filter capacitor. The ripple caused the TL1451AC IC to be unstable and eventually shutdown the output signal. Replacing only the filter capacitor solved the DELL E153Fpc LCD Monitor shutdown problem.

Conclusion, don’t always presumed that LCD Monitor is very tough or difficult to repair. From the above article, you could see that the caused of the shutdown problem was only a bad capacitor. If you fully understood how LCD Monitor works, then chances for you to successfully repair the monitor is very high but again it depends on the availability of spare parts. If you ever come across any LCD Monitor sent to you for repair for the first time, go ahead and start troubleshoot it. Who knows one day LCD Monitor repair could become one of the major source of income to you and your business.

Tags: Dell, E153Fpc, Monitor, Problem, Repair, Shutdown

Repair a stuck pixel on an LCD Monitor with this neat and easy trick.

Tags: Monitor, Neat, Pixel, Stuck

Learn How To Repair LCD Monitor

It is common knowledge that in almost all cases it is better to know how to repair lcd monitorcomponents than to substitute them. There are many reasons for this. LCD screens endure up to 10 years. In the case of LCD screens, the lifespan is even longer. Nonetheless, a screen can become unusable if a tiny part fails. Substituting the whole screen would be sound if the main transformer or the tube fails, for instance. Otherwise, repairing is the economical option. Also, repairing is also a more environmental friendly option, since monitors hold some types of metallic elements that are potentially dangerous. And, most importantly, repairing is cheaper than the purchase of a fresh electronic part.

And this is where Jestine Yong’s LCD Repair guidebook comes in handy. It consists of a step by step program that instructs you everything you want to know related to how to repair lcd monitor. White display, display shutdown after a couple of seconds, power with no display, dim display, are just some of the standard problems known to happen with LCD screens that are covered in this course. Everything that I’ve tried from his guidebook works and there are also some astounding bonuses that you get with the course. This guidebook is highly advocated to anyone who wishes to how to repair lcd monitor or just wishes to gain some money repairing other peoples LCD screens. This is a secure occupation these days, due to the fact that there are some pricey LCD screens out there and you cant just throw it out the window.

So, check out Jestine Yong’s product and you will see for yourself that this is the best guide that teaches how to repair lcd monitor. As you probably acknowledge, if you don’t have someone to guide you, troubleshooting and repairing LCD displays can be an exceedingly confusing job. That’s why I know you’re going to be pleased after you found this article, because there’s finally a secure and assured way to learn the secrets on how to repair lcd monitor.

Visit this website to learn more about this course that teaches how to repair lcd monitorema.

Tags: Know, Monitor, Repair, Want

I have a lot of friends that have LCD monitors (I prefer CRT still) and most of them are complaining about stuck pixels and how they can repair a LCD monitor that has this type of problem. I will show you 3 simple ways that you can use to get rid of this problem without having to go to someone else and maybe pay that respective person. Stuck pixels usually appear because the liquid inside the LCD monitor is not spread properly, and so 1 or more pixels may remain stuck with one color or just stay black, it depends. But now lets get down to the explaining part. 1. I will start with the software method, since this is the one that most people prefer and it is also the easiest way to repair LCD monitor that has a stuck pixel. I have 2 software programs that can do this and they are free, just search on the internet and you will find plenty of them. 2. Trying to repair the problem using pressure. What you have to do is, start by turning off your LCD monitor and then find something like a pen that has a small rounded end but it is still thin, you must use this since if it is too sharp you may scratch your LCD. Then get a small damp cloth to protect your LCD monitor from scratching, fold the cloth in 2 and place it exactly over the stuck pixel and start adding a small amount of pressure on it with the pen, DO NOT press hard or you will risk to further damage your LCD monitor and also DO NOT add pressure anywhere else besides that pixel. Now, while adding pressure on it, turn on your LCD monitor, then remove the pen and the stuck pixel should be gone. 3. And the third method is fixing the stuck pixel by tapping. Start by putting a black background on your display, and I mean black and make sure you leave your lcd monitor turned on. Then get a pen or something thin but with a rounded end and start to gently tap the stuck pixel until it disappears,you should have a steady hand for this so you wont tap other pixels. You know that you’ve added enough pressure on your taps if the screen glows white around the pixel. It should fix it after a few taps. I hope this article helped you in some way, and you may repair your LCD monitor’s stuck pixels. As a final note I want to add that there is no guarantee that these methods will work, you try them at your own risk.

Tags: BROKEN, Monitor

bit.ly Lcd Monitor Repair how to repair lcd monitor like professional, step by step learning, money back guarantee

Tags: Monitor, Repair

Video Cam Direct Upload

Tags: Dell, E172FPb, Monitor, Repair

This BenQ T705 LCD Monitor has a common fault of display shutdown after few you “On” for few seconds. The cause of the problem was usually a shorted one or two of the C5707 push pull transistors. Besides the shorted transistor, one also has to check the tuning capacitor for high ESR value with the help of ESR meter. If you do not own one, you can use the digital capacitance meter to check the capacitance value. However, from my experience, checking only the capacitance value doesn’t guarantee that the capacitor is good unless you confirm it with ESR meter. The reason why I emphasis on checking this tuning capacitors was because the capacitors have a high failure rate that could cause the C5707 transistor to go shorted. You also have to observe the high voltage transformer pins carefully. I had come across quite a number of shorted C5707 transistors caused by dry joints in pins of the high voltage transformer.

In this case, as usual after I have confirmed that only two C5707 transistors shorted, I began to test the tuning capacitors and check the pins of the high voltage transformer. Both the tuning capacitors found to be okay but there were dry joints in the transformer pins. Fresh solder was applied to the high voltage transformer pins and I’m ready to “On” the LCD Monitor. Guess what? The Monitor has the same symptom again which is display shutdown after few seconds! I don’t believe it as most of the time it will surely work as this is a common fault!

I started to recheck the surrounding components that have connection to the C5707 transistors but found no faults in it. Analyzing the board many times didn’t reveal any improper soldering job. There must be something that has gone wrong that had caused the LCD Monitor to shutdown. Deep in my heart I don’t suspect backlights problem because the C5707 transistors shorted was caused by dry joints in the high voltage transformer. Beside, the backlights were quite reliable for this BenQ LCD Monitor model.

Thinking back, I bought a new badge of C5707 transistors from my electronic suppliers not long ago. The middle pin (leg) is a bit shorter than the other two as shown from the photo below. I thought to myself would it be this badge of transistors that have problem causing the display shutdown after few seconds? Of course I can’t blindly suspect the transistors unless I have some proof of it. The finding begins………………

Testing the C5707 transistor with an analogue meter set to X 1 and to X 10 K Ohm doesn’t seem like it has problem. Comparing the result with an original C5707 transistor did have some difference in the X 10 K Ohm range but the reading is acceptable from my years of experience in testing transistor. The only thing that I haven’t compared is the Hfe reading. I used the famous Peak Atlas components analyzer to analyze both transistors and I could clearly see the big difference between the Hfe readings of the two transistors. The original C5707 transistor has Hfe value of 379 while the new badge of the C5707 transistor has Hfe value of 161! At last I found the answer!

I did tried replace the 4 C5707 transistors at one go with the new badge of transistors but the result was the same. Installing the transistors that have the Hfe reading of 350 to 400 solved the display shutdown problem. This circuit look like it can only work with the same type of transistor that has the quite exact Hfe value! That’s why for this type of Monitor circuit, many technicians hardly can find a suitable replacement. In other words, even if you could get the substitution transistor that have higher Volt, Amp and Watt but different Hfe value, you still won’t be able to bring the LCD Monitor back to life again. From the above test, this Monitor circuit has voice out loud and clear that it only need the same part number with the same Hfe value unless you have some similar transistor replacement specification that is identical to the original one.

For my readers that are in this electronic repairing line, although some of you may not be in the LCD Monitor repair, I hope you will absorb this information and apply it in your field. Who knows one day you would have face the same problem that I’m facing and this article could easily help you to solve your problem fast. Have a good and a blessed day!

Tags: BenQ, C5707, Monitor, Problem, T705, Transistor

Video showing the disassembly and repair of Dell E172fpb LCD monitor. From www.lcdrepair.us

Tags: Dell, E172FPb, Monitor, Repair

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The complaint for this DELL E152Fpb LCD Monitor was when switched on has power (LED lit) but no display. LCD Monitor is different from the CRT Monitor where you could feel the static at the front of the picture tube or hear the rushing sound from the high voltage produced by the flyback transformer. In LCD, if no display you won’t be able to know if the inverter board is working or not unless you use an oscilloscope to point near the inverter board and the scope could display a waveform indicating the inverter board is functioning.

A faulty main board may cause no display problem in LCD Monitor. If there is a problem in the main board, it would not send a “on” (enable) signal to the soft start circuit and no voltage will flow to the inverter IC thus no waveform produce by the high voltage transformer.

In the above case, after the cover was removed, the first thing I check was the vcc (supply voltage) to the inverter IC. This model is using the famous TL1451ACN Pulse width modulation (PWM) IC-some preferred to call it as inverter IC. Pin 9 is the VCC supply input and it should have about 12 Volts when the power is “on”. Measuring the pin with my faithful digital multimeter, it reads only about 3 volts which indicates there’s a problem in the supply line. It could be components that are faulty that dragged down the line or it could be the switch mode power supply itself that don’t produce enough power.

In order to find the answer as which section is giving problem, the first clue was that the power LED indicator lit and this prove that the IC is supplying enough power to the circuit. Another clue was that the meter is registering about 16 volts at the input of the 2A fuse. Because of these clear answers, we can conclude that the switch mode power supply is working fine. You can also use a 12 volt light bulb to confirm it. You may read my other post on LCD Monitor repair articles which talks about using 12 volt light bulb for troubleshooting purposes.

I kept on asking myself, why the voltage drop to 3 volts after the fuse. Before the fuse it reads about 16 volt but after the fuse it reads only 3 volts! I didn’t suspect the fuse, because the fuse can only either yes or no and no in between. The first circuit that I checked was the start circuit but all components checked to be okay. I even desoldered the pin 9 of TL1451ACN inverter IC just to make sure it is not this IC that pulled down the voltage.

This problem really challenges my troubleshooting and repairing skill, because almost all suspected components already checked to be working. Even the start circuit transistors (C945 & A733) I direct replaced, afraid they would breakdown when under load. The only component that I didn’t check was the fuse! By using my meter placed across the fuse, instead of getting low ohms or zero ohm reading I got 1.012 Kilo ohms! I‘ve got a surprised and don’t believe that a fuse can actually go into high ohms instead of open circuit. I always thought that a fuse is either close or open circuit. A fuse with zero ohms turned into high ohm thus the 16 volts dropped to 3 volts! I’ve came across lots of this type of fuse but this is the first time a fuse changed into high resistance.

Replacing the fuse only put the DELL E152Fpb LCD Monitor back to life. The lesson learned from here is that don’t assume that a component is always in a good working condition. You have to confirm it with your meter and if you still suspect the component is giving problem, simply replace it with a known good one and retest the equipment. Semiconductors can breakdown when under full operating voltage.

Tags: Dell, E152Fpb, Monitor, Repair