Monday 9 March 2020

REPAIR / SERVICING TV SONY KDL-42W705B

Technical description and composition of the SONY KDL-42W705B TV, panel type and applicable modules. The composition of the modules.
SONY LED
Model: KDL-42W705B
Chassis / Version: RB2G
Panel: T420HVF06.0 xxxxG
LED backlight: 74.42T35.OO1-0-DX1, T42-40-R and T42-40-L
T-CON: 42T34-C00 T420HVN06.2 CTRL BD
LED driver (backlight): 14STM4250AD-6S01 Rev1.0
PWM LED driver: BD9422EF
MOSFET LED driver: SBR10150CT, TPC8127
Power Supply (PSU): ACDP-120N02 Adapter 19.5V 6.5A
PWM Power: PWM
MainBoard: 1-889-202-22 173457422 A1998262B
IC MainBoard: CPU: X-Reality PRO CXD4748GB, H5TQ4G83AFR, Nand: TC58NVG3SOFTAIO
Tuner: TUS1-889-203-12 (173457512)
Control: IR: 1-889-245-11, Wi-fi: J20H076
Technical Specifications KDL-42W705B
SONY KDL-42W705B
General repair guidelines for TV LCD LED
If the ACDP-120N02 adapter power supply module malfunctions, the external manifestations may be different, for example, the SONY KDL-42W705B does not turn on at all and there is no indication of the indicator lights on the front panel. First of all, it is necessary to replace the swollen capacitors of the rectifier filters, if any. If the mains fuse is cut off in the power supply, in most cases a breakdown of the power key (s) is detected, which can be integrated with the PWM controller, or a separate field-effect transistor can be used. The rectifier bridge diodes and the electrolytic capacitor of the mains rectifier filter should also be checked.
In most cases, key breakdowns in switching power supplies (SMPS) do not occur for no reason and you should look for other faulty circuit elements that could provoke a defect. This can be dried electrolytic capacitors in the primary circuit, and faulty damper elements, as well as dangling resistors or punched semiconductor elements in the stabilization circuits. Possible defective PWM PWM chip from the manufacturer.
If, when you turn on the TV, the image appears and immediately disappears, or is missing initially when you turn on, but the sound has other functions that work, there is a high probability of a malfunction of the display backlight LEDs or the LED driver (power converter for the T420HVF06.0 xxxxG panel illumination unit).
A malfunction in the backlight circuits often occurs due to a break in the power supply lines of the LED lines. It is necessary to disassemble the panel and check the LEDs themselves, the soldering of their conclusions, as well as the reliability of the connections in the connectors and the soldering of the conclusions of the connectors.
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 motherboard 1-889-202-22 173457422 A1998262B should be checked if there is no reaction to the remote control and function buttons, the standby indicator blinks or lights up constantly. In such cases, if the converters or power regulators of the microcircuit are working, a software update may be necessary.
In some cases, it is necessary to check or replace (if necessary) the elements of the MB board (SSB) - CPU: X-Reality PRO CXD4748GB, Nand: TC58NVG3SOFTAIO. In cases where the BGA processor is used, its malfunction is usually detected by the local heating method.
If a tuner TUS1-889-203-12 (173457512) is suspected of malfunction, first of all, it is necessary to verify the correctness of the software, as well as the presence of the necessary power supply voltage levels and data exchange pulses with the processor via the I2C bus on the corresponding tuner pins.
It should be remembered! Attempts to repair the SONY KDL-42W705B 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!

Service Manual 48 pages of 2014 for  the models ---------------------------->   KDL-32W700B, KDL-42W700B, KDL-42W800B, KDL-50W700B, KDL-55W790B, KDL-32W705B, KDL-42W705B, KDL-42W805B, KDL-50W790B, KDL-55W800B, KDL-32W706B, KDL-42W706B, KDL-42W807B, KDL-50W800B, KDL-55W805B, KDL-32W707B, KDL-42W707B, KDL-42W815B, KDL-50W805B, KDL-55W808B, KDL-42W817B, KDL-50W807B, KDL-55W815B, KDL-42W828B, KDL-50W808B, KDL-55W817B, KDL-42W829B, KDL-50W815B, KDL-55W828B, KDL-50W817B, KDL-55W829B, KDL-50W828B, KDL-55W855B, KDL-50W829B, KDL-55W857B.


The appearance of MainBoard 1-889-202-22 is shown in the figure below:
1-889-202-22
1-889-202-22 can be used in TVs:
SONY KDL-42W817B (Panel T420HVJ02.1), SONY KDL-42W706B KDL-42W706W (Panel T420HVF06.1), SONY KDL-40W605B (Panel NS4S400DND01 4-528-221-02), SONY KDL-42W705B (Panel T420HVF06.0 xxxxG), SONY KDL-50W817B (Panel T500HVF04.1), SONY KDL-42W828B (Panel T420HVJ02.0), SONY KDL-48W605B (Panel LSY480HN01-001), SONY KDL-32W706B (Panel T320HVF04.1 ).
The appearance of the power supply
Main features of the device SONY KDL-42W705B:
Installed matrix (LED-panel) T420HVF06.0 xxxxG.
The matrix control uses the Timing Controller (T-CON) 42T34-C00.
The LED driver 14STM4250AD-6S01 is used to power the backlight LEDs, it is controlled by the BD9422EF PWM controller. As power elements of the LED driver, keys of the type SBR10150CT, TPC8127 are used.
To power all the internal components of the SONY KDL-42W705B TV, an external source such as ACDP-120N02 Adapter 19.5V 6.5A is used using PWM chips.
MainBoard - the main board (motherboard) is a 1-889-202-22 module, using CPU chips: X-Reality PRO CXD4748GB, H5TQ4G83AFR, Nand: TC58NVG3SOFTAIO and others.
The tuner TUS1-889-203-12 (173457512) provides the reception of television programs and tuning to channels.