Skip to main content

Original post by: Greg ,


Electronic circuits the tend to draw the most current, will run hotter, and heat degrades electronics, so when shooting trouble,  It makes the most sense to start with those item. In LED flat screens, its the LED back light panel.

Best way I have found to diagnose a back light problem is to place the Tv in a very dark room, and turn it on in the set up menu, and using a bright flash light pointed at the screen, and see if one can observe the setup screen.

It will be very dim, but you will be able to make out the text, or something. This is the Flash Light test. This means that that the information IS being sent to the  display. The LED back light which is not working, allows the signal to the display to be viewed, in normal operation.

As mentioned elsewhere, the LED back lights are LEDs mounted in a strip. which each strip draws a good amount of DC Current,which is why a flat screen  feels warm to the touch when operating.

Changing the LED back light strips involves disassembling the many layers of the flat screen, not an operation for the faint of heart ! In that one has to be careful that the display isn’t damaged in the disassembly process, and needs to be preformed in a very Clean environment as any dust/ stuff that gets trapped between the layers will be visible all the time the display is on, assuming your successful getting it to light up again.

With the sell price of new flat screens tv coming down, ( 32 in 720 P Insignia Brand At Walmart on line this morning is $89.00.{12_29_2018}. The repair shop has no way to  a descent hourly way to pay him self, which is why I left the field in 1978.!!

If the dead flat screen is not your main go to Tv, & have a place where one can leave a flat screen disassembled for the long periods of time for the container ship to come from China to Long Beach Ca., and you work for free, then !&&* yeah give your best shot.  You Tube videos are your BEST friend.

In my experience  with no display / black screen, its the LED driver electronics.

Just my 3¢. g²