Have you ever ever had an issue with the TV the place the display screen doesn't show any image even when it’s turned on? In such circumstances, the issue would possibly point out harm to the backlight of the TV.
Because the title suggests, “backlights” are the sunshine sources to our TV display screen; no mild supply ends in no viewable image on the display screen.
Backlight harm is most definitely prompted as a result of issues in two important parts that make up the backlight: the Backlight Driver Board/Powerboard or the precise Backlight strips.
Don't worry; it's simpler to repair than it seems to be. We'll sort out every subject in an orderly trend so to repair your TV with out spending some huge cash.
Doable Causes of Backlight Failure
The backlights harm is prompted as a result of following potential causes.
Backlight Failure Signs
- TV activates with none show of the image.
- A Dim display screen factors to faulty led backlights.
- A Flickering display screen is a chance for a dying led strip.
- Darkish sections are brought on by some LED bulbs turning faulty.
- Mild Spot sections happen when the lens of those LED bulbs falls off.
- A half darkish display screen level to 1 entire aspect of Backlights is failing.
- Mild leaking from the TV’s edges signifies LED bulbs have moved contained in the TV.
Tips on how to Repair Backlight on TV?
The Backlight subject solely happens in LED TVs as QLED and OLED TVs would not have backlights. LCD TVs used backlights made up of fluorescent bulbs, however their manufacturing has now been stopped because the expertise is outdated.
Issues to Think about Earlier than Testing & Restore
- Firstly, please verify the backlight subject. A simple method is to take a white mild in opposition to the display screen. If the graphics present when illuminated, the machine has backlight failure.
- We suggest putting the TV on a delicate mat with the display screen going through down to forestall any scratches on the display screen.
- Take loads of footage on every step to hint again and reassemble the TV after repairs.
- Put screws in cups and label them in order that we don't lose them throughout reassembly.
As soon as the above concerns are factored in, open up the again cowl of the machine and begin the testing & restore course of.
Step 1: Take a look at the Energy Provide Board & Led Strips
Most TVs characteristic the led driver on the powerboard itself, however some have a separate led driver board. Discover the precise connection level the place the backlight cable connects to the board.
Issues to Think about Relating to the Testing Space
- Each board has a small chart close to the realm the place the backlight cable is related with the board. The chart will describe the optimistic and destructive factors within the connection.
- Set your multimeter setting to DC Volts.
- When testing with a multimeter, observe the person instruction given under strictly. Errors in putting lead wires would possibly quick circuit the connection factors.
- The variety of wires used to attach the backlight to the board will range in response to the variety of backlight strips. These wires are related in pairs, i.e., one optimistic and one destructive level.
Begin testing the Connection Factors
- Don't disconnect something; plug within the TV and flip it on totally.
- Take the multimeter and place the Crimson lead on one of many optimistic factors within the connection. Place the black lead within the destructive connection level.
- Take the voltage measurements for every connection level.
Take Really helpful Motion In keeping with Voltage Eventualities
If the TV didn’t have a backlight subject, every connection level would present a voltage studying of round or lower than 100 volts when the backlight is related to the board. All connection factors would present the same studying with out many fluctuations.
If the voltage studying is above 100-120 volts, Zero or near Zero, observe the really helpful motion acknowledged within the eventualities listed under:
- Unplug the TV and disconnect the backlight cable from the board. As soon as that is completed, plug the TV again in and activate the TV.
- Now use the multimeter to check the person connector pins. The crimson lead goes to optimistic factors, and the black lead will get grounded on the steel chassis of the TV.
- If voltage is above 100-120 volts, this studying signifies the board is supplying the facility correctly. We have to change the LED backlights.
- Suppose the voltage is zero or near zero. Change the Powersupply board. These boards typically vary from round $60 to $200. Discover the precise board in response to the TV mannequin quantity.
Step 2: Open the Remainder of the TV
Observe the steps under if the backlight strip must be changed. You do not want to open up the TV if the facility provide board wants substitute.
- Take away the plastic bezel frames, TV boards & steel brackets/chassis of the TV.
- Take away the ribbon cables rigorously as they're vital & delicate. The TV won't work if the harm is incurred on these cables. Don't pull on them.
- Begin eradicating the layers of the display screen with a suction cup. There can be an LCD Panel and a few white panels beneath it.
- Use painter’s tape to maintain the display screen’s prime layers collectively, stop flexing, and keep the order of screens throughout reassembly.
Step 3: Change Backlight of the TV
If the Backlight strips require substitute, learn by way of the concerns under after which proceed to switch them.
Issues to Think about Earlier than Backlight Substitute
- Change the entire set of strips or particular person strips. We don't suggest altering singular bulbs because the substitute course of is tedious and requires a heating plate.
- All the time purchase the LED Strips in response to the Show panel quantity sticker on the again of the steel chassis of the TV. The producer will specify if they're suitable with that show panel quantity.
- Bear in mind, one other model would possibly produce the Show panel. All the time purchase strips in response to the model specified within the show panel, not the TV model.
Take away Earlier Put in Backlight Strips
- Begin by eradicating the white reflective layer on prime of the backlight strips. Little plastic pegs are used to lock them; push the pegs from the again of the steel chassis with a plier or by hand to unlock them.
- Take an image of the connection space of the backlight strips with the backlight cable that goes to the powerboard. We have to be part of them precisely like it's after substitute.
- Unplug the backlight cable from strips.
- Find the two round metallic factors on the start line of every step illustrated by the pic under.
- Take your backlight tester and place the red-colored result in the + level and black lead wire to the – level. All bulbs in that strip ought to mild up in the event that they work superb; if not, we have to change the entire strip.
- Take an outdated present card , bank card or scraper and begin taking the broken strips out from beneath by sliding the cardboard beneath the strips.
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Set up New Backlight LED Strips
- The brand new led strips include double-sided tape on the backside; slide the brand new strips in place and stick them.
- Some strips have holes that we are able to use to lock them into the TV chassis. Set up them in response to your TV’s earlier backlight strips. If not one of the possibility is offered, stick the strips with some white masking tape.
- Do a closing check with the backlight tester like earlier than. All bulbs ought to mild up
- Reconnect the strips to the backlight cable with the assistance of the image taken earlier than.
Step 4: Reassemble the TV
As soon as the backlight strips have been changed, we might want to reattach the whole lot. Think about the next factors whereas reassembling the TV.
- Begin by reinstalling the white reflector sheet on prime of the backlights.
- Subsequent, place the white display screen layers (diffusion sheets) that we saved collectively on prime of the reflector sheets.
- Verify for any lint, fingerprints, or painter’s tape throughout this step and take away them accordingly.
- Reinstall the panel body on prime of the white display screen layers and set up the LCD panel on prime of it. Ensure that the panel is recessed contained in the body as failure to take action would possibly lead to cracks later.
- Reattach any metallic braces. They normally click on onto the display screen if aligned & positioned correctly.
- Connect all ribbon cables to their respective locations. Use footage taken earlier than. Be additional delicate with them as they simply break.
- Reinstall any metallic brackets left on prime of the whole lot. These frames ought to clamp on the chassis of the TV.
- As soon as the whole lot is secured, reconnect the ribbon cable from the again of the metallic chassis to the scan drive board. Additionally, begin putting in the TV boards on the steel chassis behind the TV.
- Rescrew the again cowl of the TV and plug within the TV to an influence supply.
Fixing backlights is feasible with a DIY method, but it surely does require fundamental information of how present, wires, and multimeters work. When you have doubts, we don't suggest tampering with the TV. Backlight fixes are historically a job for professionals.