Monday 9 March 2020

REPAIR / SERVICING TV SONY KDL-42W706B

Technical description and composition of the SONY KDL-42W706B TV, panel type and applicable modules. The composition of the modules.
SONY LED
Model: KDL-42W706B KDL-42W706W
Chassis / Version: RB2G
Panel: T420HVF06.1
T-CON: T420HVN06 2CTRL BD 42T34-C00
LED driver (backlight): 14STM4250AD-6S01 Rev1.0
PWM LED driver: BD9422EF
MOSFET LED driver: SBR10150CT, TPC8127
Power Supply (PSU): ACDP-120N02 19v5 6A2.
MainBoard: 1-889-202-22 BAX L board // 1-889-202-12 (173457412)
IC MainBoard: CPU: X-Reality PRO CXD4748GB, H5TQ4G83AFR, Nand: TC58NVG3SOFTAIO
Tuner: TUS
Technical Specifications KDL-42W706B
SONY KDL-42W706B
General repair guidelines for TV LCD LED
Diagnostics of malfunctions and repairs SONY KDL-42W706B, as well as other electronic devices, it is recommended to start with an external examination of the external and internal elements. It often happens that visible damage to elements or connections helps determine the direction of the troubleshooting. Ring cracks in the soldering of the leads of the heating elements, swollen electrolytic capacitors, a charred paint layer on the resistors - all this for the repairman can be a significant clue in the assumptions about the causes and consequences of the malfunction.
Sometimes the SONY KDL-42W706B TV simply does not turn on. No control lights on the front panel are lit or blinking, the TV does not respond to the remote control and does not make any sounds or any signs of life when turned on. The most likely cause of the malfunction is the failure of the ACDP-120N02 19v5 6A2 general power supply module. If it is serviceable, you need to check the processor batteries on the SSB (Main Board). Diagnostics and repair of the common power supply should always begin with a check of the mains fuse and the condition of the electrolytic capacitors of the secondary rectifier filters. Defective and swollen capacitors should be replaced with new ones. If the fuse breaks, it is advisable to check for a breakdown, first of all, all the power semiconductor elements of the converter and the diode bridge of the rectifier network, as well as the large electrolytic capacitor of the filter of the rectifier network.
As a rule, the keys in switching power supplies (SMPS) are reliable enough and rarely fail for no reason to be looked for by checking other components of the circuit - electrolytic capacitors, resistors and semiconductor elements of the primary circuit. The PWM chip is verified by replacing it with a known good one.
If the SONY KDL-42W706B does not have an image, but there is sound and the TV is controlled by the remote control, a malfunction in the backlight circuits of the T420HVF06.1 panel is likely. The LEDs or the power converter - LED driver may be faulty. Often in such cases, when you turn on the TV, an image appears and immediately disappears. First of all, it is necessary to verify the operability of the electrolytic capacitors of the rectifier filter supplying the LED driver, and check the LEDs, connecting obviously known good diagnostics.
In most cases of lack of backlight, it becomes necessary to disassemble the panel in order to check the LEDs, connectors, loops and all contact connections. If one or several LEDs does not work in one line, therefore, they are broken and should be replaced.
When diagnosing, it is necessary to take into account that it is impossible to check the open in the chain of LED lines without disassembling the panels using a tester or multimeter. To open all PN junctions connected in series, a voltage of the order of several tens of volts is required, and ideally, a current source.
On the BAX L, TUS ,, motherboard, in case of a malfunction, you should first check the operation of all the stabilizers or power converters of the microcircuits and, if necessary, update the software (software).
It should be remembered! Attempts to repair the SONY KDL-42W706B 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-42W706B:
Installed matrix (LED-panel) T420HVF06.1.
The matrix control uses the Timing Controller (T-CON) T420HVN06.
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.
The formation of the necessary supply voltages for all nodes of the SONY KDL-42W706B TV is carried out by the ACDP-120N02 power module, or its analogues.
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 TUS tuner provides television reception and channel tuning.