Thursday 9 April 2020

REPAIR / SERVICING TV AIWA 42LE3120

Technical description and composition of the TV AIWA 42LE3120, type of panel and applicable modules. The composition of the modules.
AIWA LED
Model: 42LE3120
Chassis / Version: V1K10
Panel: LC420EUN (SD) (V1)
LED backlight: 3660L-0374A
LED driver (backlight): integrated into PSU
Power Supply (PSU): 168P-P42EWB-HCW0
PWM Power: FSFR1700XSL, OB5223AP, OB6572CP
MainBoard: KDL42MS18A -I-SDV1 35015556
IC MainBoard: EN25B64
Tuner: NoName
Specifications 42LE3120
AIWA 42LE3120
General repair guidelines for TV LCD LED
Possible malfunctions
- AIWA 42LE3120 TV does not turn on. There are no signs of operability. The indicators on the front panel do not light or flash, the TV does not respond to the remote control and control buttons.
In such cases, the fault should be sought first in the power supply module 168P-P42EWB-HCW0. It is necessary to measure its secondary output voltages, and if they are absent, check the power switches and rectifier diodes in the converters for a short circuit.
In case of breakdowns of semiconductors in the secondary circuits, the converter can usually work abnormally in the short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse 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 circuits (OOS) of stabilization. PWM controllers (PWM) FSFR1700XSL, OB5223AP, OB6572CP, if they do not have visible damage to the case and open short circuit between the terminals, are usually checked by replacement.
- There is no image, there is sound, it responds to the remote control. Or the image may appear for a second when turned on and immediately disappears.
In most of these cases, a malfunction is detected in the nodes and backlight elements of the LED panel. The reason can be both in the power supply of the LEDs, in their serviceability (breakdown or breakage), as well as in the violation of the contact connections of the LED strips.
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, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the KDL42MS18A motherboard should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (software). If it is not possible to replace the MB (SSB) card, it is necessary to check the health of its elements - EN25B64. Defective components should be replaced.
In cases where there is no 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 NoName tuner. 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.
We recommend the owners of the 42LE3120 TV for repair only to qualified specialists with the necessary work experience! Self-repair attempts without the appropriate knowledge and skills can lead to irreversible negative consequences!


FIRMWARE FOR SPI FLASH  ----------->   AIWA 42LE3120 V1K10, Main: KDL42MS18A -I-SDV1 35015556 , Panel: LC420EUN (SD)(V1)




 Key Features of AIWA 42LE3120:
Installed matrix (LED-panel) LC420EUN (SD) (V1).
To power the backlight LEDs, a converter is used, combined with a power supply.
The necessary supply voltages for all nodes of the TV AIWA 42LE3120 are generated by the power supply module 168P-P42EWB-HCW0, or its analogs using the FSFR1700XSL, OB5223AP, OB6572CP microcircuits.
MainBoard - the main board (motherboard) is a KDL42MS18A module, using EN25B64 chips and others.
The NoName tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC420EUN-SDV1
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 930.24x523.26 mm
Surface: Antiglare (Haze 10%), Hard coating (3H)
Brightness: 360 cd / m²
Contrast Ratio: 1400: 1
Display Colors: 16.7M (8-bit), CIE1931 68%
Response Time: 6 (G to G)
Frequency: 60Hz
Lamp Type: WLED Embedded (LED Driver)
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V
 Trademark: AIWA, Model: 42LE3120.
Briefly from the TV: LCD, LED backlight, 42 ", 1920x1080, 1080p Full HD, DVR, sound: 10W, HDMI connectors: 4.
The composition includes MainBoard KDL42MS18A -I-SDV1 35015556 and LCD panel (matrix) LC420EUN (SD) (V1).
Power Supply Unit (PSU) 168P-P42EWB-HCW0 Power Supply.
AIWA 42LE3120 TV with an LC420EUN 42 ”(107 cm) diagonal LCD display in 16: 9 format. The required screen brightness of 360 cd / m² is provided by LED backlighting. Dynamic contrast ratio of 40,000: 1 is achieved by special control of the LEDs. In this model uses side lighting from Edge LEDs.
The LC420EUN (SD) (V1) panel and the KDL42MS18A motherboard software provide for watching programs and movies in high quality HD at a resolution of 1920x1080 pixels in a graphical decomposition according to the standard 1080p (Full HD). The input high-frequency or video signal can be processed in analogue systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p.
Supported media file formats: MP3, MPEG4, JPEG.
The power of the sound system 10 W (2x5 W) provide two speakers. The audio processing system NICAM STEREO is used.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, audio x2, component, VGA, HDMI x4, USB x2. An output for connecting headphones is provided. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector is used on the TV case, this interface supports resolutions: 640x480, 800x600, 1024x768, 1360x768, 1920x1080. The digital tuner is capable of receiving television channels in DVB-T MPEG4 standards.
The power consumed by the TV working in the network mode is 135 watts.
Overall dimensions: 1019x690x255 mm.
TV mass: 15.8 kg.
Attention! The LC420EUN (SD) (V1) panel of an AIWA 42LE3120 LED TV is an expensive and unreliable element.
Avoid any impact on the glass and pressure on the surface of the screen to avoid damage to the LED panel!
It is also unsafe to get liquid on the screen. Sometimes one drop is enough if it flows down the glass onto the cables so that the TV becomes unrepairable.