Technical description and composition of the SONY KDL-42W808A TV, panel type and applicable modules. The composition of the modules.SONY LED
Model: KDL-42W808A
Chassis / Version: RB1G
Panel: LC420EUF (FF) (P2)
LED backlight: 6922L-0064A
T-CON: 6870C-0446C
LED driver (backlight): integrated into PSU
PWM LED driver: CXA3854M-T6
MOSFET LED driver: MDF3N50
Power Supply (PSU): APS-342 / B 1-888-356-21 GL2E
PWM Power: CXA3810M (PFC & PWM resonant), MIP2H2 (StandBy)
MOSFET Power: KF7N50F, TK15A50D (PFC)
MainBoard: 1-888-101-31 (173415631)
IC MainBoard: CPU: CXD4739GB; NAND Flash: TC58DVG3S0ETA00 (TC58NVG3S0FTAI0)
Technical Specifications KDL-42W808A
SONY KDL-42W808A
General repair guidelines for TV LCD LED
Repair of electronic devices, including the SONY KDL-42W808A TV, it is advisable to start with an external examination of its external and internal elements. Often, by the visible signs of a change in the state of some elements, one can judge the causes of the defect. Elements with visible damage, for example, capacitors swelled up after boiling the electrolyte, charred resistors in certain nodes of the circuit, as well as ring cracks in solders will help the master to guess the causes and possible consequences of the malfunction.
If the KDL-42W808A TV does not turn on, does not make any sounds when turned on, and also no indicators on the front panel light or blink - there is a high probability of a malfunction in the power module. In some cases, there may be a malfunction only in standby power. When diagnosing and repairing the power supply, first of all, replace the swollen filter capacitors of the secondary rectifiers and check the fuse and, if it is broken, it is necessary to identify the cause. Often in such cases, an avalanche (thermal) breakdown is detected in the power semiconductor elements of the module — rectifier diodes and transistors in the primary circuit.
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 chip from the manufacturer.
If the SONY KDL-42W808A TV does not have an image, but there is sound, a malfunction in the backlight circuits of the LC420EUF FF P2 LED panel is likely.
In case of breaks in the LED circuit, a complete disassembly of the panel is required, the LEDs are checked for an open circuit, as well as the reliability of the connections in the connectors and rations of the terminals.
To check the LED lines for breaks without disassembling the panel, for example, a current source will help. It is impossible to open series-connected PN junctions with a simple multimeter, a voltage of the order of several tens of volts is required.
Diagnosis and repair of the motherboard 1-888-101-31 usually begins with a test of the performance of the stabilizers and power converters of the module chips. In some cases, a software update is required.
In cases of complex repairs of MB (SSB) and in the presence of the necessary skills and equipment, sometimes it may be necessary to replace its NAND Flash chips: tc58nvg3s0ftai0; and other possible malfunctioning components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
Remember! Attempts to self-repair by users of the SONY KDL-42W808A TV without the appropriate qualifications and necessary experience can lead to serious negative consequences!
Service manual / Schematic Diagram --------------> Sony KDL-42W802A/805A/807A, KDL-42W808A/809A, KDL-47W802A/805A/807A/808A/809A, KDL-55W802A/805A/807A/808A/809A chassis RB1G
PSU / Schematic Diagram --------------> APS-342/B Power Supply schematic diagram
The appearance of MainBoard 1-888-101-31 is shown in the figure below:1-888-101-31
1-888-101-31 can be used in TVs:
SONY KDL-42W808A (Panel LC420EUF (FF)(P2)), SONY KDL-46W905A (Panel YLV4621-02N), SONY KDL-40W905A (Panel YLV4021-02N).
PSU Advanced
The KDL-42W808A TV is equipped with the APS-342 / B 1-888-356-21 GL2E power module using the PFC (Power Factor Correction) circuitry acting as an active filter to eliminate the higher harmonic components of the current consumption. The boost converter based on the CXA3810M & PWM resonant PWM controller does not allow the input rectifier filter's electrolytic capacitor to be connected to the network directly through open diodes, when the reactance (about 15-30 ohms at a frequency of 50 Hz) determines the charge current. As a result of the conversion, the charging current of the capacitor will be determined in such a way that the envelope of the high-frequency pulses of the input current will repeat the phase and shape of the sine wave of the input voltage. The health check of the PFC unit is carried out by measuring the DC voltage on the capacitor of the rectifier network. In operating mode, it should be around 380V, in standby approximately 300V.
The appearance of the power supply
Main features of the device SONY KDL-42W808A:
Installed matrix (LED-panel) LC420EUF (FF) (P2).
The matrix control uses the Timing Controller (T-CON) 6870C-0446C.
To power the backlight LEDs, a converter is used, combined with a power supply, controlled by a CXA3854M-T6 PWM controller. As power elements of the LED driver, keys of the MDF3N50 type are used.
The necessary supply voltages for all nodes of the SONY KDL-42W808A TV are generated by the APS-342 power module or its analogs using CXA3810M (PFC & PWM resonant), MIP2H2 (StandBy) microcircuits and power switches of the KF7N50F, TK15A50D (PFC) type.
MainBoard - the main board (motherboard) is a module 1-888-101-31, using CPU chips: CXD4739GB; NAND Flash: TC58DVG3S0ETA00 (TC58NVG3S0FTAI0) and others.
