Hi 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?
Sorry 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?
Hello, 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.
@bejones269 When 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.
I 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?
@Zundwig When 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..
If 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.
@bandet888 The 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.
@GrantsPassTVRepairs So 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?
@GrantsPassTVRepairs Now 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!
i have a question, I have an Olevia 42 inch its about 3 years old. The picture went out and turned black. There is sound. Do you have any idea what could have go wrong , And what parts do i need to fix it?? Thanks, hope to hear from you soon,
A real common cause for the kind of problem you described, is that the back lights on the TV are not operating due to a bad inverter board, but it's difficult to guess at problems like this with out seeing the set. I'm assuming this is an LCD TV.
yes the tv is an lcd. The tv also smells like burned wires . It turns on but the picture is black. There is sound coming out of the tv. And thank you for the fast response!!!!!!!!!
I have almost the same problem. Westinghouse 32" LCD TV Monitor almost 4 years old (picture is there but not viewable - you can see what's on the display by shining a flashlight on the screen, audio is fine, no burnt wire smell). I've found lots of posts online pointing to replacing the backlight lamp; your suggestion that it might be a bad inverter board. Appreciate the insight and the videos - very helpful stuff and I especially appreciate the pop-ups you have added - nice job!
I have a Samsung LNT3242HX/XXA same problem as the 32" westinghouse as described above. Im getting about 1 second of backlight when the TV is first powered on. Is that an inverter problem or a bad ccfl?
You can shine a light of your own behind the screen and see if your picture is there. That will at least confirm if there are additional problems other than the light circuit, but because of the way the feedback circuit works sometimes its hard to draw the dotted lines between the symptom and the cause.
I would start with the power supply capacitors and move on to the inverter board to see if your transformers are open or the lights themselves are bad. From what I'm hearing on the new LED sets they have a feedback circuit which can shut down the power supply if it senses a problem in your lights or the associated output transformers which often go open.
I've verified that the LCD is working after that one second of backlight using the flashlight trick. Im getting normal audio as well. After watching the video on capacitors, I tried the hairdryer trick on the 4 caps on the inverter board. I heated them up before turning the tv on, but the heated caps didnt do the trick. Also I tested the voltage to the inverter board and its reading 24.4V. According to a samsung troubleshooting guide on this model, its needs to be 24V. Thanks for the quick post
That trick with the hair dryer will not work if the capacitors are to far gone. Since you may not be able to get parts on your TV any way, it might be fun to see what kind of back light you can come up with on your own such as LEDs. I recently saw a youtube video on this. Perhaps more work than the TV is worth, but if your the experimental type it might make a fun project.
In your experience with samsung lcds, what part is more likely to be the faulty part? the inverter or the CCFLs?
Ive found both parts online, but I dont know which part I should pursue. CCFLs - $10 to 12 a piece. Inverter board $70. I got the bad TV from my dad, who was going to throw it out, so if I can spend about $100 and a few hours to get it running again, Id say its worth it.
Also, if it is the CCFLs, do they all go bad at once? or could one bulb be the cause for the other 11 not to power on? Is it a series or parallel circuit? would I need to buy 12 new ones or just a few of them?
Yeah he's right. One bulb can throw off the inverter, remove the CCFL's and one... maybe two will probably be really black on the ends. But, if you're in there and replacing lamps you should probably do all of them
One additional thought. It could also be that just one of the inverter transformers has gone bad, and or the related circuitry which drives them. but they might not sell you a single transformer anyway. I have not repaired enough LCD sets to tell you which is more likely to be bad between the inverter board and the lights.
Yes there is. Using your volt ohm meter you can put it on the resistance scale, and measure across the primary and secondary side to see it its open and or has any shorts. Since you may not know what the resistance should be, try measuring some of the other inverter transformers, and see how they read in comparison. If you had what's know as a ring tester that
I bought a replacement inverter on ebay, but I got the same results, 1 second of backlight. I was able to return it, so I will buy some new ccfls and see if that fixes it.
Also 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
I 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.
This 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?
Hi 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?
skmaduev 3 months ago
Sorry 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?
1961vampire 5 months ago
@1961vampire I would suspect you may have some back light problems related to the inverter board and or cold cathode fluorescent lamps.
GrantsPassTVRepairs 5 months ago
Hello, 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.
bejones269 7 months ago
@bejones269 When 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.
GrantsPassTVRepairs 7 months ago
I 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?
Zundwig 9 months ago
@Zundwig When 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..
GrantsPassTVRepairs 9 months ago
thank you for the tips
drannard123 1 year ago
@drannard123 Glad you found the helpful
GrantsPassTVRepairs 1 year ago
You sir, are a wealth of knowledge.
oo1o11oa 1 year ago
If 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.
bandet888 1 year ago
@bandet888 The 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.
GrantsPassTVRepairs 1 year ago
@GrantsPassTVRepairs So 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?
bandet888 1 year ago
@GrantsPassTVRepairs Now 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!
bandet888 1 year ago
Clearly understood grant!!Thanks
mickeygovender 1 year ago
I learnt lot of tips from your videos, thank you very much for shearing
safeburn 2 years ago
the best you tube site I ever found?
keep up the good work... you happen to have block diagram how lcd-plasma tv works?
philip2go 2 years ago
i have a question, I have an Olevia 42 inch its about 3 years old. The picture went out and turned black. There is sound. Do you have any idea what could have go wrong , And what parts do i need to fix it?? Thanks, hope to hear from you soon,
jaymanuelraida29 2 years ago
A real common cause for the kind of problem you described, is that the back lights on the TV are not operating due to a bad inverter board, but it's difficult to guess at problems like this with out seeing the set. I'm assuming this is an LCD TV.
GrantsPassTVRepairs 2 years ago
yes the tv is an lcd. The tv also smells like burned wires . It turns on but the picture is black. There is sound coming out of the tv. And thank you for the fast response!!!!!!!!!
jaymanuelraida29 2 years ago
I have almost the same problem. Westinghouse 32" LCD TV Monitor almost 4 years old (picture is there but not viewable - you can see what's on the display by shining a flashlight on the screen, audio is fine, no burnt wire smell). I've found lots of posts online pointing to replacing the backlight lamp; your suggestion that it might be a bad inverter board. Appreciate the insight and the videos - very helpful stuff and I especially appreciate the pop-ups you have added - nice job!
cvisme 2 years ago
Here is a video where the gentleman modified his LCD back light to work with an LED.
watch?v=BExEo-d1qkc
GrantsPassTVRepairs 2 years ago
I have a Samsung LNT3242HX/XXA same problem as the 32" westinghouse as described above. Im getting about 1 second of backlight when the TV is first powered on. Is that an inverter problem or a bad ccfl?
Thanks
Great videos! Keep them coming!
taygrib76 2 years ago
You can shine a light of your own behind the screen and see if your picture is there. That will at least confirm if there are additional problems other than the light circuit, but because of the way the feedback circuit works sometimes its hard to draw the dotted lines between the symptom and the cause.
GrantsPassTVRepairs 2 years ago
I would start with the power supply capacitors and move on to the inverter board to see if your transformers are open or the lights themselves are bad. From what I'm hearing on the new LED sets they have a feedback circuit which can shut down the power supply if it senses a problem in your lights or the associated output transformers which often go open.
GrantsPassTVRepairs 2 years ago
I've verified that the LCD is working after that one second of backlight using the flashlight trick. Im getting normal audio as well. After watching the video on capacitors, I tried the hairdryer trick on the 4 caps on the inverter board. I heated them up before turning the tv on, but the heated caps didnt do the trick. Also I tested the voltage to the inverter board and its reading 24.4V. According to a samsung troubleshooting guide on this model, its needs to be 24V. Thanks for the quick post
taygrib76 2 years ago
That trick with the hair dryer will not work if the capacitors are to far gone. Since you may not be able to get parts on your TV any way, it might be fun to see what kind of back light you can come up with on your own such as LEDs. I recently saw a youtube video on this. Perhaps more work than the TV is worth, but if your the experimental type it might make a fun project.
GrantsPassTVRepairs 2 years ago
In your experience with samsung lcds, what part is more likely to be the faulty part? the inverter or the CCFLs?
Ive found both parts online, but I dont know which part I should pursue. CCFLs - $10 to 12 a piece. Inverter board $70. I got the bad TV from my dad, who was going to throw it out, so if I can spend about $100 and a few hours to get it running again, Id say its worth it.
Thanks
taygrib76 2 years ago
Also, if it is the CCFLs, do they all go bad at once? or could one bulb be the cause for the other 11 not to power on? Is it a series or parallel circuit? would I need to buy 12 new ones or just a few of them?
taygrib76 2 years ago
I can't speak for every design, but I was told many of them have feedback circuits which turn off the whole set when one of the lights has a problem.
GrantsPassTVRepairs 2 years ago
Yeah he's right. One bulb can throw off the inverter, remove the CCFL's and one... maybe two will probably be really black on the ends. But, if you're in there and replacing lamps you should probably do all of them
potc420 2 years ago
One additional thought. It could also be that just one of the inverter transformers has gone bad, and or the related circuitry which drives them. but they might not sell you a single transformer anyway. I have not repaired enough LCD sets to tell you which is more likely to be bad between the inverter board and the lights.
GrantsPassTVRepairs 2 years ago
is there a test I can try on the inverter transformers?
taygrib76 2 years ago
Yes there is. Using your volt ohm meter you can put it on the resistance scale, and measure across the primary and secondary side to see it its open and or has any shorts. Since you may not know what the resistance should be, try measuring some of the other inverter transformers, and see how they read in comparison. If you had what's know as a ring tester that
GrantsPassTVRepairs 2 years ago
This has been flagged as spam show
Can I test them while they are still in the board?
taygrib76 2 years ago
I would start by testing them on while they are soldered on the inverter board to see if its open or has real high resistance
GrantsPassTVRepairs 2 years ago
I bought a replacement inverter on ebay, but I got the same results, 1 second of backlight. I was able to return it, so I will buy some new ccfls and see if that fixes it.
taygrib76 2 years ago
Also 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
taygrib76 2 years ago
I 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.
taygrib76 2 years ago
Sounds like your making great progress.
GrantsPassTVRepairs 2 years ago
The new bulbs worked and my tv problem is solved.
This 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?
taygrib76 2 years ago
Very nice. good tips. thanks
anno32 2 years ago
I'm glad you found them helpful. I hope to add more when I have the time.
GrantsPassTVRepairs 2 years ago