How to Troubleshoot TV with Backlight but no picture. Philips 40PFL3705 Backlight no video repair.
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- Опубликовано: 3 янв 2022
- If your Television's screen lights up but there's no picture, image, or words on the screen, its just a blank backlit screen; then most likely the cause is either a bad T-Con board or a bad LCD Panel/screen.
In this video we have a Philips LCD TV model 40PFL3705D/F7 that powers on with backlights but no image. I will show you how to troubleshoot it to isolate whether its the T-con board or the LCD panel.
Even though this Philips model is an older CCFL backlit TV, the troubleshooting method is still the same on all Televisions that use a T-Con board.
Here are a few more good videos on how to troubleshoot Televisions with Backlights but no picture on the screen.
• Backlight but no displ...
• 60" Samsung No picture...
FOR TOOLS AND TEST EQUIPMENT:
bigdogelectronics.us/
KAIWEETS MULTI-METER USED IN VIDEO:
kaiweets.com?sca_ref=1488882.UqPmA1Bjbh 
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You are such a fantastic teacher.
Thank you! 😃
Your "disconnect 1 flex cable" helped me to solve my issue. After disconnecting 1 cable the half of the picture was visible, then i saw that the second cable had broken pins at the end which was causing shorts. So i used scissors to cut the damaged part and now the tv is working. Thank you very much :)
Thank you so much! Only suggestion I have would be to give your troubleshoot rundown that you did at the end, at the beginning of the video. Your process was well explained and easy to follow. Thanks so much!
Thank you Big Dog! I have the LG 50UH5530-UB that you did a video on. I knew almost nothing about electronics and I was able to follow along and replace the LED backlights. It still wasn't working, so I started troubleshooting the T con board using one of your videos. Turned out that I hadn't slid the Ribbon cable into the motherboard all the way. Once I did that, Voila!! Tv works like new. You're a fantastic teacher and your videos are the best!! Thanks again.
Nice and clear walkthrough on troubleshooting a TV.
was waiting for a new video, thanks man. You know we all appreciate ya
More to come!
Great teacher! Enjoying your videos!
You're the boss, always interesting ! thank you to take time to explain...
And this is why one should use surge outlets to prevent spikes from reaching the electronic devices.
During bad electrical storms, I unplug my devices even if they are plugged into a surge device.
Nice diagnostic and repair Bigdog!
Thats always the Best method.
The power supply is a switch mode power supply so it has a very wide range of input mains voltage tolerance, so a surge protector would not usually be needed. SMPS have clamping diodes.
The only problem I saw was using a ammeter to measure current bypassing the fuse.. An ohm measurement from ground to the circuit side of the blown fuse would indicate if there was a high current path to ground. If there was, the ammeter fuse would blow, and if it was a dynamic short, one that requires the downstream load o have a voltage across it to turn on a path to ground. A safe wat to test that is to tack resistor across the blown fuse with a value calculated to limit current to , say, 1/2 the fuse rating.
Generally, fuses blow for a reason powering the downstream circuit with a programable current limited power would all safe trouble shooting without further damage to the defective board. I think there was a current limiting supply on the right side of the work bench. A frequent cause of such problems in equipment a few years old are dry electrolytic capacitors... They age faster than solid state capacitors.
Thanks for sharing your knowledge, I think I'll give that dead-screen Philips that I acquired another repair attempt.
Good Video My Friend thanks for sharing i Just fixed my wife TV the same model just did like u said just replaced the fuse on TCon board and it work. Wala like u said. Thanks again and God Bless you.
Glad it helped
Appericate the video man good job!
I hope that you are well off financially, have a side job or have some way of financing yourself. The reason I say this is because you can possibly have more fans than finances because you are giving up your game. People could possibly want only advice and not your business. Over time this could become very frustrating. Mostly because you took all of these classes but not receiving any compensation. You are quite good at what you do and I admire that as well as your excitement. You made me pull out my gear and opened my shop back up. I stopped about 10 years ago and started doing other ventures that proved to be more financially stable. It can be a good form of income but I gave away too much information and people started to repairing their own devices and they no longer needed me as much, unless they ran into a problem they couldn't fix. Keep up the good work and don't stop. I started in 2003 and ended with honors. Thanks for the boost I am working on a TV now but I can see where I am very rusty and need to hit the ground running.
Appreciate that, but now since everybody's seeing me on RUclips, I got waaay more service calls, phone calls, & emails than I can handle, thats not even including the nice money I get from my RUclips channel. Thats funny, cause my buddy told me the same thing years ago about giving away free info and people where going to take business away from us cause they could do it they self. I found out it was just the opposite. If someone in Chicago see's my Video vs. the world; the chances are pretty slim that I'ma lose business just in my work radius. I'm only limited to my service area (Chicago). So maybe I lose 1 out of 50 people cause they decided to try it themselves. Of course I can only speak for a Television repair business. Blessings in your electronics repair business.
@@bigdog8882 I am very glad to hear that. I got the Blues real bad when I started. I had to have my head down when I walked the street...lol. You keep up the good work soldier. Did you start out doing good or it take some time? I started out strong but dwindled down. I also had a good amount of competition in this small town.
@@vernonjohnson1147 Been doing dis nonstop since 1995. I feel like Im gettin too old for this shi.. now. Tired of going to peoples houses & taking TV's off the wall, lol.
@@bigdog8882 wow you have been doing it awhile!
One of the best ways to grow a tech business is giving away information. I had a large recording studio in California from 1972 to 1993.. It had 3 studios in one custom building.. With some luck and great staff and desirable location 600 miles from LA, good bands hated recording in LA because record company suits always wanted to hang out in sessions and cause problems. We recorded 197 gold and platinum albums. When the recording industry died in the early 90s because of digital file copying the labels would not property fund the typical 3 month recording projects... So I retired but being busy earning income since I was 13 years old in electronics, I started doing field maintenance of the few remaining recording studios,, who really could not pay much with their drop in demo recording.. To keep my hand in it, I started repairing guitar amps, power amps and tape decks. That was fun and easy but word of mouth was a slow way to build a customer base.. I went to the manager of the largest music store in the area and suggested to have a amplifier weekend. Anyone with an amp that they wanted tested or if it had a simple problem, fix it on the spot from a raised platform in the center of a room large enough to handle about 100 people at a time. I brought all the test gear including low distortion generators, spectrum analyzers, several oscilloscopes and a few chests full of tubes and common parts.. Set up like a master chef might for a cooking class and a pa system. It was fun for me and the crowd was overflowing so we decided to carry it over a second day. I gave honest estimates on thhe condition on each and explained every step and why... Some I had to tell the owner the unit really was in too poor condition to be a reliable gigging amp,, others, if they only needed adjustments or bias setting or a few new tubes I replaced them for free...It was a great success for the store, which sold new amps after an expert opinion suggested what they brought was not suite to their goals.. Most I fixed while keeping up banter and explaining what the meters scopes and spectrum analyzer was telling me. The two days were tiring but for most of the attendees, no one had ever explained why they amp sounded the way it did.. At the time I was doing it at home in one of my garages as a hobby business. Within 2 weeks,, I was swamped with work and my live in GF did not like all the musicians hanging out so I rented a commercial nearby. I was pretty efficient but could not keep up with inflow.. I hired a guy who was eager to close his small shop and work for me. He was very experienced with guitar amps, In 6 months we were swamped and the girl I hired for office work, part ordering and customer contact were working at peak output so I needed to expand again so I could seek contracts for warranty repair.. mostly so we had direct factory access to parts.
I leased a large R&D modern building with 34 car parking lot, landscaped grounds and built a beautiful modern customer area.. It was 5000 sq feet, 3x the size needed. My other hobby was refurbing HP, Tektronix, GR Sound Technology test equipment and had a large collection mostly from surplus sales or test gear swap meets once a month in Silicon Valley which was still the center of electronics test gear... None of it cost much, there was no eBay to drive up prices at that time. When the shop was finished, in 2 weeks I had built 20 well equipped work benches.. I took photos of everything and moved gear around so the benches were each fills with top test instruments so it looked like each bench has $50k in test gear, but we had two girls in the front and 4 techs and photos of 20 loaded benches and sent all the manufacturers we had problems getting parts from. The service center application forms always asks for a list of test gear and photos of the benched to make sure it was a real business instead of some working at home..
It was a very impressive list, and which had listed model and serial numbers for every piece, 532 different HP, Techtronic's or other top test instruments. The result was all but one company took us on a warranty station.. So suddenly we had all the factory service manuals and software test routines for the digital equipment.. By the end of the year we had 23 techs and 4 girls in the showroom and office... We expanded again 8 months later by leasing the 5000 sq ft attached warehouse with a loading dock. Two large companies shut down their entire factory service making us the "factory". It was the largest pro audio service center in the world. THAT is what giving away information and advice did. Equipment was shipped in from all over the world, and semis pulled up at thee shipping dock unloading hundred of warranty units once or twice a week..
In 2000 I gave it all to the employees and moved out of the at age 51 for the first real break I had but that lasted 3 months before I got the bug to start a small business in a field I had no experience with and did not know the language.. 12 months later I had 68 employees. It was seasonal work so that left me October to mid April off. I paid all the staff all winter so every one traveled. I have been in 92 countries..
As one man shop, specialize in a single brand or even model so parts stock and and tech data is easier to master and focus on collector items or ones with growing value....Small easy to ship items means you can seek customers all over the world,, such as vintage microphones where a refurb might be $500 and take one day. Do not target high end hi-fi, it all a cult and the weirdest people are involved so one day you are the master but one nonsense complaint will ruin your business. Don't try to make a killing on each repair.. We built tthat large shop on volume and efficiency so some models were flat rate so we could speed through them without waiting for estimate approval.. one third of out business was other shops sending gear to us because we did so many and had all the parts for some models we could make a profit on $50 for a charge other shops charged $100 because we did so many of the same model that repair was fast,, on one sitting. Steady high volume on specific models was very efficient with no down time for parts. I wrote a shop database system that automated warranty claims, and a list of all prior repairs with the same model and symptoms would popup as the tech began checking it. The girls at the front counter picked up very fast so they knew the models better than the owners. That meant if a problem was intermittent, they could coach the owner on reproducing the problem. That save a great deal of tech time when a customer makes a statement of a unit being faulty when it is actually something else it is connected to where the problem is. Let the owner demo the problem because tech time was more valuable and often the owner did something that triggered it and a tech approaching it cold would be lucky to stumble across the combination of actions the customer did that triggered it...By keeping hard to reproduce intermittent problems of the bench saved $50,,000 a month. Everything was available at the front counter to get it to happen so put that off on the customer and counter staff. If you do not specialize .techs spend more time on tracking down tech data and parts than odd jobs are profitable. Parts are hard to find so have enough space for Junkers because most parts for anything over 10 years old are not even available anymore. Vey few manufacturers stock parts for anything not still under warranty.
Good luck but be smart on setting up your repair business.
Good job
Congrats
good job!
What double sided tape do you use to hold the screens back in place after changing backlights on a tv like the Samsung un65ks8000
It was screaming fuse to me lol, they don’t make them like that anymore that’s for sure
Great video BD
Yeah thats for sure.
nice 1 bigdog
@bigdog8882 I know this is a stretch but I'm new to fixing or troubleshooting boards. I've replaced panels and backlights but that's all. My issue is my LG led tv screen randomly went black when I turned it on months ago and figured I would try to fix it. My backlights do work and it has sound. I tried the do the ribbon cable test from panel to t-con board. I removed one and did nothing stayed dark. This is what I don't understand when I removed the other one, my tv went half white and half dark but still no picture. Appreciate the help if you respond 🙏
Happy customer!
Hey BigDog. I´ve got a Philips LED tv. Same problem as this video. I unplugged the left side of the 2 flat cables=nothing/same black screen/only backlight. When I unplug the right flat cable=left side of the panel lights up(white). This would mean a bad Driver Board? Some of the capacitors on the driver board are open.
Had that with a main board on an early Insignia LCD 32" made in 2008.
Excellent video!!!
When you replace a fuse, do you leave the TV on for any certain amount of time to make sure it doesn’t blow again?
No not really. It should blow right away if there is a short.
It would be nice if he gets up here and answer some of these questions I appreciate him anyways I'
My son and I are trying to fix his tv he uses for his school work ( we homeschool). Hisense 32k20dw, there is sound and can see video with a flash light but barely. The info I found indicates the green board for one issue, white board for the other issue. I have a volt meter but no further electrical specialties. I’m still watching the video, but hope to discover a method to pinpoint if its a board issue or other.
nice
Thanks
Good day Sir I have Sony xbr-65x900b tv at it had no backlights with sound so I bought a power supply board put it in now I have backlights sound but still no picture...Any Suggestions?
So what fuse did you use to replace it i have 12 v going in and nothing coming out
Thanks for sharing! I recently received a 65" Mi TV with white screen. Voltage for both VGH and VGL keep fluctuating. Could you advise whether changing the T-con board will solve the issue?
Unplug each side of the panel connectors and see if it still fluctuates. If still fluctuating then yes; change T-con board.
@@bigdog8882 Ohhh thanks! Will test it!
@@bigdog8882 I unplugged both of the ribbons and re-measured the VGH and VGL. Voltage measurement still fluctuating. I have recorded the testing video.
ruclips.net/video/E-xsnZTWyx4/видео.html
Is it faulty T-con?
Hello! I have a 65in toshiba tv. There is power, and a faint light comes on and there is sound, but no picture. I aready replaced the psu. Will the t-con fix my problem?
Hallo, honestly I'm not into electronics but in my country some of them they want a lot money to fix it, even when is something small as a problem.
I have a similiar problem with 58 inch Philips, model 2020 (58PUS7505/12), and I'm wondering if I change the main board is it going to work or something else?
Thank you in advance!
Bought a non functional 19" Sanyo for 20 bucks off e bay from a guy who said it stopped working after a power surge and it was only an 80 cent glass type fuse to get it back on again!
i have that same problem with 2 tvs of mines hopefully i can get it fix
By the way the tv model is 40PFL3705D/F7 philips 40inch.
On this same video same tv I replaced all the boards in the back using parts from a source that test all the boards before you get them., However, I still get no sound and just a blue screen. I even watched your video over and over and the only thing I did not see a need to do is the fuse jump. Also I don't know where to get that fuse you used in the video. If you could please let me know where to get that fuse I would be grateful as well as help with the tv.
Good evening!!
I need your assistance with my television
Hey Big Dog. I’m located in Chicago and have tried several trouble shooting procedures to no avail. I either don’t have the tools or something just ain’t working. Is there a way to hire you to check it out?
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Hi, great Video! What is the Titel, from the background Song? Thanks
"On the Wing"
I have a TCL Roku TV 55in TV still can hear it playing backlight is still on screen is blackish blue with no picture not showing homescreen either can you troubleshoot this for me
Its either the T-con board, or a bad LCD panel.
nice repair,thanks.Can you pls tell me the model of the dig.meter that you used in the video,i like it.
Check description. Thanks.
kaiweets.com/products/kaiweets-km601-digital-multimeter?sca_ref=1488882.UqPmA1Bjbh
Thank you very much,i am going to get 1 tomorrow.
@@jorgemiret1148 No problem, make sure that you used that Link I gave you, that way I'll get credit for it and you should get a slight discount at check out. Greatly appreciated! Happy new year!
Main board?
i have an issue where i have nothing but a standby light... there is no voltage at The 12 v fuse on the Tcon ... i can unplug the ribbon cable which supplies the 12 v to the tcon and my backlight comes on i can plug it back in and it kills the Lights ..i have taken off both ribbon cables that feed the panel from the Tcon and it still acts like something is shorting i have checked and i do have 12 volts on the ribbon cable that i unplug..Any thoughts ??
Brand and Model please
@@bigdog8882 Its a Vizio 3D tv Model = M501d - A2R ....LG T-Con Board 6871L-3270B3 ...Thanks
I'm not a expert but definitely sounds like a shorted tcon and I would just replace it it should only be like $10
What about sound is there sound
What if I have what if the screen lights up but it doesn't do anything?
can someone pls explain what did he do actually and what is the main problem ? im so confused sorry english isnt my main language
I have a Phillips 2022 with the same ass problem bro, so is just Phillips they are like that.
Could you come to my house please
If it was manufactured in Nov. 2010 then it will be only 12 years old this month not 13 as you mentioned (2022 - 2010 = 12).
A little more complicated than usual but what a weird looking fuse & not the easy little glass type.
So there's instances where the led panel is bad/defective and technically there's nothing one can do to fix correct?