Category Archives: TV Repair

Vertical Bands on LED TVs

I have seen panel failures with wide vertical bands. The vertical sections are fed by flex connectors TAB (Tape Automated Bond) bonded to panel boards at the bottom of the TV. TAB bonding uses expensive specialized equipment and ripped connections are not economically repairable. The flex connector could also contain an embedded COF (chip on flex) IC. If the IC fails, there could be artifacts within the vertical band. If the flex is completely ripped off, the corresponding vertical section will be dark with no signal. Liquid (such as windex) trickling into the bottom of the bezel can also damage the panel boards. Random single pixel vertical lines are also panel damage and not repairable. You can google the Sony Tcon Training Manual to see examples of other panel failures.

Flex connector ripped off at bottom of the TV

Westinghouse WD40F2610 Shuts Off

This smart TV was reported to be shutting off on its own. When I plugged it in, it appeared to be fine but when I connected via wifi to the internet, it started to shut down after a few minutes. This model uses an all-in-one combination board with no separate wifi module that can be replaced. In order to factory reset it, I had to turn off my wifi and use the remote code menu-0-0-0-0-0-0 to get to the service menu. This model is similar to Element brands as well. I tried using wired ethernet and the TV shut off as well. Replacement of the board would be more than the value of the TV.

Samsung UN55NU6900F LED Backlight Replacement

The Samsung NU series has a high rate of backlight failures causing dark vertical bands or dark sections of the screen. See post here. The one repaired here has the right side dark. The backlights are edge lit from the bottom and running in Dynamic mode and at maximum level will tend to burn these out pretty quickly.

This model has two strips with each wired in left and right banks. Though only one side was bad, I replaced both with new strips. Part number is AOT_55_NU7300_NU7100_2X40_3030C There are a few sellers on ebay.

I was lucky and the light spreading inner panel was not burnt by the hot LEDs.

Edge lits are very finicky and any imperfection will cause an uneven backlight or bright spots.

Toshiba 55TL515U Fan Error

This TV had a fan error displayed on the TV. Removing the back cover showed the fan caked in dust. I vacuumed and sprayed duster on it and it was spinning when I turned the TV on. You can see the location above the VGA port so you may be able to clean it without removing the back.

Factory Reset Your Samsung Smart TV if Apps are Slow

If your apps are running slow or giving errors, you should try a factory reset.

1. With TV off.  Press Mute-1-8-2-Power and TV should come on with the service menu.  Hit OK on OPTION, OK on Factory Reset and OK again on Factory Reset.  You should just press OK three times in a row.  TV should reset.  Be very careful in the service menu since you can brick your TV changing things.

2. Go through the setup wizard and complete it to the end

Backlight failure is common in LED TVs. Keeping the backlight level at around 55% will make them last. I would also recommend turning off eco sensor which automatically adjusts the backlight level based on the ambient light.

3. Turn off Eco Sensor: Menu ->System->Eco Solution  – Turn Eco Sensor OFF
4. Turn down the Backlight: Menu -> Picture  Set Backlight level to between 10-12.  It should apply to all sources by default.

Motion smoothing will sharpen images for fast actions like sports but will make movies too sharp and look like soap operas.
5.  Menu -> Picture ->Picture Options  Turn OFF LED Clear Motion

Sony KD-60X690E 6 Blinks

This 2017 model Sony TV wouldn’t turn on but gave a 6 blink error code. 6 blinks according to the service manual is a backlight problem. Luckily, new strips are relatively cheap. This model uses the style of LEDs that also turn blue. With a new set of backlights, the TV turned on with a picture. With this model, backlight appears can be turned down in the BRIGHTNESS picture mode setting. I would recommend setting to about 50% to prevent future failure.

Info on LED backlight failures here

Info on LEDs turning blue here.

Samsung UN46F6350AF Doesn’t Turn On

UN46F6350 UN46F6350AF UN46F6350AFXZA UN46F6350AFXZC

This TV would attempt to turn on but didn’t with no backlight and no video. Unplugging the cable from the power supply to the main board, the backlights came on. This test indicates that both the backlights and power supply were likely good.

Next test was to power up only one side of the panel at a time between the tcon and the panel. I got a picture and the TV was on with the right side disconnected. There appeared to be a short in the panel on the bad side so I blocked a few pins on the outermost edge with tape and this allowed the TV to turn on with a clean image. I used the procedure explained in this post.

Samsung NU Series Backlight Failures

There are lots of reports on the reddit tvrepair subreddit of NU series TVs with failed backlights. NU is a 2018 model year and backlights are failing after 2 years. These models are edge lit from the bottom so LEDs that have burnt out will cause dark vertical bands or sections.

Some model numbers include

UN50NU6900F UN55NU6900F UN55NU6950F

With the screwless back cover and edge lit design, replacement can be pretty difficult especially on a large screen.

It is always recommended to never run your backlights at maximum which shortens their life.

Another reddit post shows that the LEDs can melt the clear plastic panel that spreads the light behind the panel. When it is melted, the gap will create bright spots on the bottom. The heat can also crack the panel which will show up a vertical bright line above the LEDs.

Here is what edge lit LEDS look like behind the panel. In the NU series design, there are fewer LEDs and they are spaced further apart. They run both brighter and hotter.

Update – I repaired a UN55NU6900F. Details here.

Update 2 – Here is a UN55NU6800F with a burnt light spreading panel and crack caused by the heat from the LEDs. The crack will appear as a bright vertical line in the backlight.

Burnt light spreading panel with vertical crack

Samsung UN50H5203 No Power

Model UN50H5203 UN50H5203AF UN50H5203AFXZC AH01 UN50H5203AFXZA

This TV had no power and didn’t turn on. The standby voltage was low indicating a damaged power supply. This model year does suffer from backlight failures and probing the connector to the LEDs indicated a lot of shorted ones. I suspected the bad backlights had damaged the power supply though the FET and diode for the LED driver tested good. With the LED connector unplugged, the standby voltage was normal again and the TV could power up. I confirmed the screen was good and I was getting video. I ordered replacement strips and a new power supply board since I suspected the LED controller was damaged.

Panel part number DF500BGA-B1
Power supply BN44-00772A
LED strips (4 rows) LM41-00001Q LM41-00001Z 2013SVS50

Repair of flickering double image horizontal lines on a TV

Flickering and double images and horizontal lines are symptoms of a bad panel and typically not repairable. However there may be a workaround by blocking pins to the panel.

Flickering image TCL 43S517

To determine if this workaround will work, first make sure your TV has a separate Tcon board. Newer TVs may have integrated Tcon boards so you will be out of luck in this case. Next, you will need to power up the TV with one side of the TV connected at a time to see if one side will display a good picture. With the TV unplugged, disconnect the ribbon from the tcon to the panel one side at a time. It is locked in place by a flip lock that will need to be lifted up to unlock.

If one side shows a good picture, you can try the technique in these youtube videos and block connections on the bad side. When inserting and removing the ribbon cable, it will be safer to UNPLUG the TV between attempts.

If the tape cutoff method doesn’t work, the very last resort is to look for side tabs on the bad side (if there) and rip them completely off.

Why Does This Work?

The panel is driven by drivers which drive both the left and right side and if one side has failed, blocking the connection to them will block the faulty drivers but the other side can maintain the picture. The analogy would be if one kidney was causing you pain so we remove it but you still have a second kidney.

How Long Does This Last

This workaround could last years or until the other side fails.

Troubleshooting TCon or Panel Issues

The Sony T-Con training manual linked here shows examples of both tcon and panel failures.

Update: Some new youtube videos from Frugalrepair about this fix

Update 2: There may be hope for models with integrated tcon boards as shown in this video.