Tuesday 10 March 2020

REPAIR / SERVICING TV SONY KD-55XE8577

Technical description and composition of the SONY KD-55XE8577 TV, panel type and applicable modules. The composition of the modules.
SONY LED
Model: KD-55XE8577
Chassis / Version: BMK
Panel: V550QWME04
LED backlight: Edge LED 3 channel
T-CON: 55T36-CO4 CTRL BD
LED driver (backlight): 125.3V 0.69A
Power Supply (PSU): APCP-209A1 B 2955041900
MainBoard: 1-982-022-31
IC MainBoard: SPI Flash: MX25L3233F, MX25L1636E
Tuner: SUT-CE551ZP (D2856ER)
Technical Specifications KD-55XE8577
SONY KD-55XE8577
General repair guidelines for TV LCD LED
Possible manifestations of defects
- SONY KD-55XE8577 does not turn on and does not show any signs of performance at all. Does not blink indicators and does not respond to control buttons.
In such cases, the fault should be sought first in the APDP-209A1 power supply module. Then we recommend that you measure its output voltages and, if they are absent, you should check the health of the power switches and rectifier diodes of the converters for a probable short circuit.
In the event of breakdowns in the secondary circuits of the converter, it can usually fail in short circuit mode, and in the event of a short circuit in the power elements of the primary circuit, the mains fuse or current sensor at the source of the key most often breaks.
Breakdown of power switches (MosFet) in pulsed sources is sometimes caused by malfunctions of other circuit elements, for example, in circuits supplying a PWM controller, frequency-setting or damper ones, as well as in negative feedback (OOS) stabilization circuits. PWM controllers (PWM), if they do not have visible damage to the chassis and open short circuit between the terminals, are usually checked by replacement.
- There is no image, but there is sound and reaction to commands from the remote control. Or the image appears immediately after turning on and disappears.
Often in such cases, there is no LED backlight. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
It should be remembered that it is not possible to determine the open circuit in the LED lines without disassembling the panels with a tester or multimeter without an additional device, for example, a current source. To open all PN junctions connected in series at once, a voltage of several tens of volts may be required. Then it is necessary to open the panel and check each LED separately with a multimeter. If the capabilities of your multimeter do not allow you to open the LED in the forward direction or dual LEd are used, then the PN junction of the emergency zener diode can indirectly serve as a health indicator. In case of LED-a failure, the zener diode PN junction will either be cut off or broken into short-circuit.
- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the motherboard 1-982-022-31 should begin by checking the stabilizers and power converters needed to power the microcircuit and matrix. If necessary, update or replace the software (software). Often, the MB (SSB) card must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - SPI Flash: MX25L3233F, MX25L1636E and failed chips replace with new ones. Some malfunctions may be due to the use of BGA soldering technologies in modern Main Board technologies. Typically, such defects are detected by local heating of the chip.
In the absence of tuning to the channels of on-air or cable television, you should make sure that the software is correct, as well as in accordance with the ratings of the supply voltage at the terminals of the tuner SUT-CE551ZP (D2856ER). It is also necessary to check the presence of pulses of data exchange between the tuner and the processor via the I2C bus using an oscilloscope.
It should be remembered! Attempts to self-repair a SONY KD-55XE8577 TV, in the absence of the necessary qualifications and experience, are categorically not recommended and are fraught with negative consequences, up to the complete non-repairability of the device!




The appearance of MainBoard 1-982-022-31 is shown in the figure below:
1-982-022-31
The appearance of the power supply
Main features of the device SONY KD-55XE8577:
Installed matrix (LED-panel) V550QWME04.
The matrix control uses the Timing Controller (T-CON) 55T36-CO4.
To power the backlight LEDs, the 125.3V LED driver is used.
The formation of the necessary supply voltages for all nodes of the SONY KD-55XE8577 TV is carried out by the APCP-209A1 power module, or its analogues.
MainBoard - the main board (motherboard) is a module 1-982-022-31, using SPI Flash chips: MX25L3233F, MX25L1636E and others.
Tuner SUT-CE551ZP (D2856ER) provides the reception of television programs and tuning to channels.



Brand: SONY, Model: KD-55XE8577.
Short from TV: LCD, LED backlight, 54.6 ", 3840x2160, 4K UHD, HDR, DVR, 3 TV tuners, sound: 20W, HDMI connectors: 4, Internet access, Wi-Fi, Bluetooth, Smart TV.
On the official site of Sony there is firmware (Firmware) - a software update to version 6.6520 from 06/30/2019.
The composition uses MainBoard 1-982-022-31 and LCD-panel V550QWME04.
Power Supply Unit (PSU) APCP-209A1 B 2955041900 Power Supply.

The SONY KD-55XE8577 TV with a V550QWME04 LCD display, a diagonal size of 54.6 "(139 cm) is a 16: 9 aspect ratio. This model uses side illumination from Edge LEDs.
The V550QWME04 display and software (software) of the 1-982-022-31 board provide for viewing in high quality 4K UHD with a resolution of 3840x2160 pixels in the 4K UHD, HDR standard. Image processing is performed using modern High Dynamic Range (HDR) technologies with an extended range of brightness gradations.
The KD-55XE8577 TV has built-in SMART Software and pre-installed Android Operating System. Connecting to the Internet can be done via Wi-Fi. Video processor supported media file formats: MP3, WMA, MPEG4, HEVC (H.265), Xvid, MKV, JPEG.

The power of the sound speaker system 20 W (2x10 W) is provided by two speakers. It uses a NICAM stereo signal processing system and Sound Surround.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV x2, component, HDMI x4, USB x3, Ethernet (RJ-45), Bluetooth, Wi-Fi 802.11ac, Miracast. An output for connecting headphones is provided.
The digital tuner is capable of receiving television channels in the standards DVB-T MPEG4, DVB-C, DVB-T2, DVB-S2.

The power consumed by the TV in the operating mode from the network is 180 watts.
Overall dimensions: with stand 1232x772x252 mm, without stand 1232x717x57 mm.
TV Weight: with stand: 19.5 kg, without stand: 18.6 kg.
Attention! The V550QWME04 panel of the SONY KD-55XE8577 LED TV is its most expensive element.
Avoid hitting the glass and excessive pressure on the screen surface to avoid damage to the LED panel!
It is unsafe to get any liquid on the screen. Sometimes one drop of water is enough, if it flows down the glass onto the cables, the TV can become unrepairable.