Last week my 55-inch Sony Bravia KD 55XE9005 LED HDR 4K Ultra HD Smart Android TV suffered an unfortunate accident with a friend who was playing Richie's Plank Experience on my Oculus Rift. While playing one of the bonus levels she ran across my room and straight into the TV while trying to get away from a virtual bus.
At first, we thought the only damage to the screen was only scuff marks which wiped off with some glass cleaner but after powering on the TV, I found the full extent of the damage with the centre part of the display not working and a large crack across the lower part of the screen as you can see on the photo below.
As the television was now dead and a replacement panel didn’t appear to be available to repair it, we decided to strip it down to see what you get inside a £1000 LED HDR 4K Ultra HD Smart TV before taking the bits to the local recycling centre.
The back cover was held on with cross-head screws around the edges and middle.
With the rear plastic cover removed it revealed the circuit boards and mounting brackets on the back of the TV. At the base of the TV are a pair of slimline speakers and between these are three small PCBs, one with an infrared receiver and the second with a WiFi module and antennas and a third with a single IC which we haven’t been able to establish what it does.
Above this is the display driver board and in the centre of the TV panel is a large PCB which is the LED backlight driver.
On the left of the TV is the power input board which uses a DC socket from an external 19V power supply, and this board has input filtering capacitors and inductors.
The right side holds the main input and processing circuit board which has a small RF input daughter board fitted into the lower edge.
After removing the circuit boards and cables you are left with the display panel and wall mounting bars which are held together with several small screws. The edge of the screen has a plastic and metal bezel which is held on with more small screws. The display panel part number was: YD7S550DND01B A2187580A.
Removing these screws allows you to lift the LCD panel away which revealed the damage from the VR impact. The LCD panel has two long PCBs at the bottom which connect via flat flex to the screen and two connectors to connect to the display driver board.
Under the LCD panel are several layers of light-diffusing material comprising of a Reflective Polarizer, Prism Sheet, Diffuser plate and Reflective sheet.
Under these are the backlight LEDs with a white reflective layer of plastic which is taped down along the edges.
The LED strips are mounted onto aluminium strip PCBs and these are held to the metal chassis using double-sided tape.
The glue holding the LED strips onto the back-metal panel was softened using a hair dryer and this allowed us to remove the LED strips from the TV.
All board locations listed below are when viewed from the back of the television.
Power Input PCB
Located on the left side of the TV, this has a power input socket and power filtering and regulation components.
RF Input daughterboard PCB
The RF input PCB is located on the lower-right side of the TV and is connected to the main input and processing PCB via a header connector. There are a pair of RF input ICs marked Sony D2856ER
Wifi module and antenna PCB
This small PCB located at the bottom of the TV has a WiFi and Bluetooth module which is marked as J20H088 and is made by Foxconn
Infrared Receiver PCB
This small PCB located at the bottom of the TV has an infrared receiver module and also a small light sensor.
Unknown function PCB
This small PCB located at the bottom of the TV has a single 5-pin IC marked TA7 184 and two capacitors. I haven't been able to find any information about this chip or its function.
Display Driver PCB
The display driver PCB is located at the bottom of the TV and has a Samsung VTU13B1C display controller IC which appears to be a commonly used 4K display driver on different brands of televisions.
LED Backlight Driver PCB
The LED backlight PCB is in the centre of the TV and contains driver ICs and power regulation for the LED backlight arrays which are connected by three flat flex cables. The main driver ICs are OZS16TN which are made by O2Micro International Ltd. The manufacturer doesn’t have any datasheets available for this IC. There is also an ARM STM32F071 microcontroller which is an ARM Cortex-M0 Access line MCU with 128 Kbytes Flash, 48 MHz CPU and CEC functions.
Main Processing and Input PCB
The main processing and input PCB contains the HDMI inputs and outputs and connects to the other circuit boards via ribbon cables and other higher-power connectors. The main processor is a Mediatek MT5832DG1U with a second processor marked MST7411FD
Reusing the LED strips
As we now have 14 aluminium-backed LED strips with 105 LEDs overall, we are planning to use some of these for lighting our CNC milling machine and lathe.
We have tested the LEDs using our current limited power supply and each LED illuminates at 12 Volts and 160mA which is approximately 2 watts for each LED.
The LEDs are connected in strips of three on the PCBs and so we can either create a current-limited 36 Volt power supply or cut the PCB traces on the PCBs and solder wires to the test points on each side of the LEDs to power them from a 12 Volt supply.