#Phone screen lights up but no display series#
#Phone screen lights up but no display tv#

Now we simply have to test each strips individually to see if they light up or not. The thing with 9v batteries is that they are made to be plugged with one another! So you just need to put some cables on both ends and there you go. It’s less then the optimal 32.4v required but not that much lower, it might be able to light the strip a bit so we can identify which is not working.

#Phone screen lights up but no display series#

So, I took 3 9v batteries that were laying in a drawer, put them in series to make a virtual 27v battery (3 x 9v). That’s the maximum voltage we do NOT want to exceed, otherwise LEDs could be damaged during testing. By looking up this model online, I found out that the ones used on those strips need 3.6v so as there are 9 LEDs per strip: 3.6 x 9 = 32.4v input voltage required to light a single strip. One LED like those ones typically needs between 2.5-3.6v input voltage to light up.

Professionals use LED testers such as this one (about 40$ on amazon) but as I didn’t had one at the time, I decided to make one, McGyver style! 🤓 Using a multimeter, we can confirm that the strips are indeed set in series, so now we have to test each strip individually.

Note: If you look closely, you’ll see that one looks different than the others! 3rd strip from the top, 6th LED from the left. Most LED backlight systems have strips set in series, meaning that if one of the them fails, all the system goes dark… First thing to do is look for burnt LEDs. So, let’s remove that white cover which is part of the light diffuser to have a good look at the backlight.Īs we can see, the backlight system is made of 5 LED strips. The first one is a classic LCD panel with a LED backlight, whereas the second is an OLED panel that doesn’t need any backlight as it is integrated in each pixels (making the spare parts much more expensive by the way).

#Phone screen lights up but no display tv#

LED backlight is the most common thing these days, but do not mistake an LED TV with an OLED TV. Note: Older TVs have neon tubes for backlight, which is thicker and less exposed to this kind of failure. Here we can see that the backlight system is made of LEDs which is pretty simple to replace when being the cause of the failure. Now that LCD panel is removed, we can remove the bezel that maintain the backlight diffuser and access the backlight itself. Be very careful with the panel as it is extremely fragile! Remove the front housing then the LCD panel Turn the TV around to remove the front housing and the LCD panel. Detach the 2 ribbons on the bottom of the screen from the board In my case, with a Samsung F5000, I had to process as follows: Disassemblyįirst we have to remove the back housing to reveal the boards (from left to right: main board, T-CON, power supply) and disconnect the LCD panel from the T-CON board. That implies disassembling the TV to access the backlight which is between the LCD screen in the front and the boards in the rear.

Now that we now the image itself is fine, this means the main board is probably fine too, so we are going to test the backlight system itself. The image would be very dark, like turning the brightness of the screen very very low. To do so, the easiest way is to power on your screen, put a flashlight very close to it and check if you can see the image through. As backlight failure is a very common issue, this is the first thing to test. The first step into repair is to find the root cause of the issue.

As the repair costs for that kind of TV is pretty low, considering repairing it yourself might be a good idea! Diagnosis This problem on low-end TVs often occurs within the first couple years. One of my relatives had this exact symptom happening all of a sudden. In this post, we’ll take a look at the latter and at one way to fix it.

Defective capacitor on the power supply board.

Ever had your TV showing nothing but a black screen even if the audio was working? Unfortunately, that’s a common issue with low/middle-end LCD/LED TVs these days… Even more frustrating, this issue often comes from a rather tiny and cheap component that can be easily replaced.