LCD TV Repair made easy #4 - LCD Television
LCD TV Repair made easy #4
tvrepairinfo.com In this video I show the importance of measuring the current or the power your TV is using as a way of determining if there are any shorted parts. I also show the value of using a variac transformer to find shorted circuits before you apply full power. Ifyour a professional looking for more understanding on how repair LCD TVs or an electronics hobbyist here are some great resources. Troubleshooting & Repairing LCD TVs by John Preher at http For someone new to electronics the first few pages of this book may be a bit challenging but the majority of this book is easy reading with lots of pictures,diagrams and useful troubleshooting techniques. Johns book gives you a good idea about the main test points you should look for and their approximate voltages. ======================================== How to troubleshoot and repair Switch Mode Power supplies by Jestine Yong at davestv.jestinemichellepow.click2sell.eu This book is a bit spendy but I'm still glad I purchased it. In my opinion it's a must read. Jestine is good at getting right to the main points you need to understand about troubleshooting this kind of power supply and its associated feedback circuits. Since a majority of the problems I have seen on LCD TVs are related to bad power supplies I figured it will pay for itself many times over. Most of the book was easy reading with plenty of pictures and diagrams. ======================================== Testing electronic components and finding unknown ...
[Video Rating: 4 / 5[/random]
LCD TV Repair made # 2 - LCD Television
LCD TV Repair made # 2
tvrepairinfo.com Many of my repair techniques are not found in books but nevertheless they can be very useful in trying to quickly find out what's wrong withyour TV. If your a professional looking for more understanding on how repair LCD TVs or an electronics hobbyist here are some great resources. Troubleshooting & Repairing LCD TVs at http For someone new to electronics the first few pages of this book may be a bit challenging but the majority of this book is easy reading with lots of pictures,diagrams and useful troubleshooting techniques. Johns book gives you a good idea about the main test points you should look for and their approximate voltages. ======================================== How to troubleshoot and repair Switch Mode Power supplies by Jestine Yong at davestv.jestinemichellepow.click2sell.eu This 271 page book is a bit spendy but well worth the money. Even though I already own 3 video tapes and several books which cover switch mode power supplies this book beats them all. Jestine doesn't have perfect English but nevertheless he is excellent at describing the main points we need to understand about troubleshooting this kind of power supply and their associated feedback circuits. Since a majority of the problems I have seen on LCD TVs are related to bad power supplies It's especially helpful to learn from someone with so much hands on experience. ======================================== Testing electronic components and finding unknown resistor values by ...
[Video Rating: 4 / 5[/random]
Every time I watch your videos I learn something. Thanks for sharing your "tips".
ReplyDeleteThanks for reply...ur video on Panasonic board (Vid#10) that 450v 10uf caps were replaced and that the adjacent transformers and two invertors? also need to be checked. In your response you say it points to the main board. Does this mean that I may need a power board (or that wasn't the problem in the first place) or that I need the main board with the tuner and everything on it. Seems you can buy 32" LCDs for 3-4 hundred and I have 100 into this one now......your recommendation?
ReplyDeleteSounds like a possible main board problem. You gave me a clue when you mentioned how UN-pluging the TV resets the panel light. If you watch some of my videos at TV REPAIR INFO . COM you might find it helpful. Especially the one I did on a Vizio TV.
ReplyDeleteHave a TLX 032 TV, plug it in a red led light comes on. Push the power button and the red led turns blue. No Sound or picture.. To switch off (turn out blue light) it must be unplugged. Do that and you hear a static noise from the speaker as this is done. Could you please use your experience and point me to the right board or the place in the TV where I should start looking. I already soldered in the two 450uf caps in it and they seemed (visibly) fine. Don't know what else to do. Tks
ReplyDeleteHi I have an AOC L32W551T LCD TV, I was watching a film via the HDMI input from my PC (separate audio line) and screen went blank while sound continued unaffected, I have opened TV and no sign of capacitor damage, when powering TV LED light is as normal orange and then green when turning TV on, screen illuminates black but cannot get any menu up....any ideas?
ReplyDeleteI would suspect you may have some back light problems related to the inverter board and or cold cathode fluorescent lamps.
ReplyDeleteSorry about my english. I have a Samsung LCD TV. When I switch it on, sound and image normally appear, but after a few seconds the image goes and the sound continue. I switch it off, and after 30 seconds I switch it on again and the same thing happens, there are saound and image, but after a few seconds the image goes. Can you tell me what seems to be the problem?
ReplyDeleteWhen a TV is struck by lightening the switching power supply is generally the first to go. Start by checking the simple things like the varistor, fuse, bridge rectifier, and the capacitor that comes after it. If your lucky the lightening didn't go beyond damaging one of those components but many times it also damages your main switching transistor, ICs, diodes, resistors and circuit traces. If the antenna was hit by lightening you can bet your tuner is probably toasted as well.
ReplyDeleteHello, I have a 38" LG LCDTV that recently quit working after we had a really bad storm. It was plugged into a good surge protector. It has audio but no video. Appears to be able to switch from all modes & still no video. Called LG & the tech had me lug it in & hit "Menu" & nothing would display. he said it would have to go into the shop. is there something i could look at quick before i take it to the shop?I do have some electrical experience in Aviation electronics, not qny on TVs though.
ReplyDeleteWhen a TV is struck by lightening the switching power supply is generally the first to go. Start by checking the simple things like the varistor, fuse, bridge rectifier, and the capacitor that comes after it. If your lucky the lightening didn't go beyond damaging one of those components but many times it also damages your main switching transistor, ICs, diodes, resistors and circuit traces. If the antenna was hit by lightening you can bet your tuner is probably toasted as well..
ReplyDeleteI have a friend. He owns a 40inch. Sony Bravia kdl-40v4100. Lightning struck his house, and now the TV doesn't work. How would I diagnos the problem? And what steps should I take to fix it, without taking it to a TV repair store?
ReplyDeleteGlad you found the helpful
ReplyDeletethank you for the tips
ReplyDeleteYou sir, are a wealth of knowledge.
ReplyDeleteNow that I think about it it makes more sense, all metals have resistivity and if ALL the current went through the coils in the meter the coils would have to be humongous to carry all that current. It makes sense to only want to have only a small amount of current to pass through the coil to give you a reading. I learned something new. Thanks!
ReplyDeleteSo even though there is a short since the meter is so low in resistance some electrons may pass through anyway? I know if two wires are in parellel current will go through both wires, is it something similar with an ammeter?
ReplyDeleteThe meter is so sensitive it still works with a short/shunt across it. The size of the shunt determines how sensitive the meter is. The same meter which is designed to measure up to 5 amps could also measure 50 amps or 500 amps with a larger shunt. I hope this helps.
ReplyDeleteIf you have a dead short between the terminals of an amp meter why would electrons pass through the meter? I'm sure the meter has ALMOST 0 ohms but can't be totaly 0 ohms as the meter needs to absorb SOME power to give you a reading. How can a meter absorb any (even minute) power if there is a dead shour across the terminals? Or can it work the same as the meter an electrition uses but then you don't even need any terminals.
ReplyDeleteClearly understood grant!!Thanks
ReplyDeleteI learnt lot of tips from your videos, thank you very much for shearing
ReplyDeleteThe new bulbs worked and my tv problem is solved.
ReplyDeleteThis inspired my to attempt to fix another samsung LCD with a slightly different problem. This tv has normal backlight and sound, but no picture. After powering on, the LCD is a dark grey color and slowly begins to fade to an all white screen. When i change the input source, the screen flashes and the transformer on the PCB starts humming. Also the led on the front is constantly blinking. Any ideas on this one?
the best you tube site I ever found?
ReplyDeletekeep up the good work... you happen to have block diagram how lcd-plasma tv works?
Sounds like your making great progress.
ReplyDeleteI reassembled the TV without the LCD panel, so I could see the lamps fire up. It turns out that one bulb is not lighting. I should have done this from the beginning. I have a nice picture of it, if you'd like to see.
ReplyDeleteAlso I reassembled the tv without the lcd panel, so I could see exactly which bulb wasnt firing. Turns out it is the 3rd bulb from the top. I got a nice picture of it too if you'd like to see it. I should have done this before I bought the inverter. I think Ill just buy 2-3 bulbs and replace the ones that look like they'll burnout next. I got a quote from ccflwarehouse for $12.95 a bulb. which was lower than $19.99 i found at 2 other sites. Ill follow up with the results
ReplyDeleteThat was awesome. I like electronics yet haven't been near them lately.
ReplyDeletei use a hairdryer to turn on the power supply on an old computer.
ReplyDeleteYou need to do some of the tests I show in my videos. You will find the complete directory to them at TV REPAIR INFO . COM
ReplyDeletei enjoy your videos im leaving a comment nice job you explain things well maybe you can tell me whats wrong and how to fix a 50 inch Toshiba flat screen stays on for a while then gets a black screen but power lights still on and then you have to unplug it and wait twenty minutes before the picture works again thanks please respond
ReplyDeletecan you give me some advice on my tv ? already checked fuses and those round things and seem ok but my tv shows a blue line across only and looks like it wants to show the full screen but can't for some reason...my tv is rca tube tv those knida new ones there selling today...any help would be so appreciated !!!!
ReplyDeleteSure you can use a multimeter, oscilloscope or frequency counter but sometimes I find my audio amp trick with an inductive loop is helpful to do quick checks with out having to touch my probes to the circuit. Sometimes I like to attach an inductive loop in series with a diode to my meter probes and quickly run the coil/inductive loop over my switching transformer because high frequency oscillations can't be heard with my audio amp.
ReplyDeleteIs the telephone amplifier overkill? Couldn't one just use a multimeter ?
ReplyDeleteThanks so much Grants Pass
ReplyDeleteVery interesting, thanks Dave
ReplyDeleteBUY a new TV if your TV Screen is cracked. Anything else we can fix. . . Accurate TV Repair & Home Theater Design Inc. . . Milwaukee Wis (414) 777-0072. . . atvrhtd@gmail.com . . FREE Estimates With service . .
ReplyDelete(414) 777-0072
hi there i have a 32" lcd tv when i turn the tv on the screen comes on but i can not get anything on the screen and some times the screen flicker. how can i fix this. thanks
ReplyDeleteI still run across neon lights in old electronics gadgets. They often put them inside small switches to illuminate the switch. Sometimes you also find them in very old TVs as well. They can operate right off the 110 line but you need to use a resistor or it will blow up.
ReplyDeleteIf you don't have any luck finding one locally let me know and I can send you one.
Dave, where do i scoop up the neon light you discuss in this video? i've been trying to track one down but have run into dead ends?
ReplyDeleteMike's TV tips has loads of CRT TVs but they are case histories not how to books.
ReplyDeleteDAMN!! Flyback transformers!!! DAMN!!!! U fixing oldschool TVs for real!
ReplyDeletedoes your friends have books on how to fix old tv?CRT?
ReplyDeletegreat tips thanks.
ReplyDelete
Thank you Dave !! Its not often that people are willing to help others so thank you and thanks for sharing.Tec
ReplyDeleteAny amplifier should work. you can use an old stereo or some computer speakers with a built in amp. This only works with low frequency switching such as when the power supply is in the stand by mode. For the higher frequency switching such as when power supply is in the run position it's best to have a meter with a frequency counter. You can use a regular multimeter by attaching a coil in series with a diode across your meter probes and placing it near your switching transformer.
ReplyDeleteThanks Grants Pass. Its really beneficial. Please tell me how can i make the Telephone amplifier which tests frequencies as u shown in your video. Please help me out.
ReplyDeletethank you for this video and tv repair tips..
ReplyDeleteThis fixed my problem, and I thank you very much. Polaroid(tm), should be ashamed for charging $275.00(us),for a $4.00 repair. 2 replaced caps. and my tv was like new.
ReplyDeleteOk well I'm going to try that and thank you very much for your help.
ReplyDeleteSadly the display on the new TVs often go bad. Color lines can also come from a bad ribbon cable or driver board but the driver board is permanently attached to the LCD display and very difficult to repair.
ReplyDelete