REPAIRING / SERVICING TV DNS K32D619

Technical description and composition of the DNS K32D619 TV, panel type and modules used. The composition of the modules.
DNS LED
Model: K32D619
Chassis / Version: KDL32PS618AT
Panel: LC320DXJ (SF) (E1) // LC320DXE-SFR1
LED backlight: 6870S-01578A LC320DXE-SFR1
LED driver (backlight): integrated into MainBoard
PWM LED driver: OCP8121
MOSFET LED driver: UF730L (TO-252)
Power Supply (PSU): integrated into MainBoard
PWM Power: FAN6755W (SOIC-7)
MOSFET Power: JCS7N65SB
MainBoard: KDL32PS618AT
IC MainBoard: Spi Flash: 25Q32, 25X10, Audio amp: TDA7491LP
Tuner: Noname
Specifications K32D619
DNS K32D619
General recommendations for TV LCD LED repair
Possible malfunctions
- TV DNS K32D619 does not turn on at all. No response to the remote control and front panel control buttons. Indicator lamps do not light up or flash.
First of all, in such cases, you should make sure that the common switching power supply (SMPS) - the AC / DC voltage converter of the mains voltage - is working. All source elements in this TV model are located on the MainBoard KDL32PS618AT. It is necessary to measure its output voltages, and if they are absent (full or partial), the serviceability of the power switches (JCS7N65SB) of the converters and rectifier diodes should be checked for a possible short circuit.
In case of breakdowns in the secondary circuits, the converter, as a rule, can operate in an emergency in the short-circuit mode, and in case of a short circuit in the power elements of the primary circuit, the mains fuse is usually cut off.
The breakdown of power switches (MosFet) in switching sources is sometimes caused by malfunctions of other circuit elements, for example, in the circuits supplying the PWM controller, frequency setting or damper, as well as in the circuits of Negative Feedback (OOS) stabilization. PWM controllers (PWM) FAN6755W (SOIC-7), if they have no visible damage to the case and an outright short circuit between the terminals, are usually checked by replacing.
- There is no image, there is sound, it reacts to the remote control. Or the image may appear for a second when turned on and immediately disappear.
Usually, in such cases, a malfunction is detected in the LED panel backlight nodes. The reason may 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.
To test the LED strips, in order to open all the transitions of the LEDs, several tens of volts or more are needed; it is best to use a current source for such purposes. The breakage of several PN junctions connected in series cannot be detected with a multimeter or tester. In such cases, it is necessary to open the panel and check each LED. If your multimeter cannot open the LED junctions in forward bias, you can sometimes detect the presence of a protective zener diode PN junction by connecting the probes in the opposite direction. If the zener diode is cut off or broken in K / Z, then the LED is faulty and needs to be replaced.
- The indicator on the front panel blinks, the TV does not turn on in operating mode, does not respond to the remote control.
Repair or diagnostics of the KDL32PS618AT motherboard should begin with checking the stabilizers and power converters required to power the microcircuits and matrix. If necessary, you should update or replace the software (software). In cases of complex MB (SSB) repairs and with the necessary skills and equipment, it may sometimes be necessary to replace its Spi Flash chips: 25Q32, 25X10, Audio amp: TDA7491LP and other possible faulty components. Malfunctions associated with the use of BGA soldering technologies are usually easily diagnosed by the warm-up method.
Before replacing the Noname tuner, if there is no tuning to the channels, you must first check the software and supply voltage at its outputs. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus

Owners of the K32D619 TV are advised to contact only qualified specialists with the necessary experience for repair! Attempts to repair yourself without the appropriate knowledge and skills can lead to irreversible negative consequences!

One of the typical DNS K32D619 faults often occurs in the LED panel LC320DXJ (SF) (E1) // GW14-0056 // GW13-0423 from LG.

External manifestations: no image, display backlight does not work. In most such cases, the LEDs are faulty, which, when checked, turn out to be either open-circuit or with broken internal zener diodes.

The LEDs must be replaced, and the maximum current from the driver must be limited to 10-20%.

DOWNLOAD FIRMWARE FOR SPI FLASH  ----------->   DNS K32D619, Main: KDL32PS618AT, Panel: GW14-0056


 DOWNLOAD FIRMWARE FOR SPI FLASH  ----------->   DNS K32D619, Main: KDL32PS618AT, Panel: LC320DXE-SFR1

 The appearance of the MainBoard KDL32PS618AT is shown in the figure below:
KDL32PS618AT
KDL32PS618AT can be used in TVs:
DNS K32D619 (Panel LC320DXJ(SF)(E1)), SUPRA STV-LC32T410WL (Panel LC320DXJ-SFE1 ).
Main features of the DNS K32D619 device:
The matrix (LED panel) LC320DXJ (SF) (E1) or LC320DXE-SFR1 is installed.
To power the backlight LEDs, a converter combined with the KDL32PS618AT main board is used, controlled by the OCP8121 PWM controller. UF730L (TO-252) switches are used as power elements of the LED driver.
The power module is combined with the MainBoard and is made according to the AC / DC flyback voltage converter using FAN6755W (SOIC-7) microcircuits and JCS7N65SB power switches.
MainBoard - the main board (motherboard) is a KDL32PS618AT module, using Spi Flash chips: 25Q32, 25X10, Audio amp: TDA7491LP and others.
Tuner Noname provides reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: LG Display
Model: LC320DXJ-SFE1
Type: a-Si TFT-LCD, CELL
Diagonal size: 31.5 inch
Resolution: 1366x768, WXGA
Display Mode: IPS, Normally Black, Transmissive
Active Area: 697.685x392.256 mm
Surface: Antiglare (Haze 1%), Hard coating (3H)
Glass Depth: 0.50 + 0.50 mm
Contrast Ratio: 1200: 1
Display Colors: 16.7M (6-bit + Dithering)
Response Time: 8/10 (Tr / Td)
Frequency: 60Hz
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V
DNS TV K32D619 with LCD LC320DXJ, diagonal size 32 "(81 cm) 16: 9 format. Contrast - ratio of maximum brightness to minimum brightness is 1200: 1. Dynamic contrast ratio 5000: 1 is achieved by special control of LEDs depending on the illumination of areas The LCD panel uses direct pixel backlighting with rear-mounted LEDs - Direct LED.
The LC320DXJ (SF) (E1) sensor and MainBoard KDL32PS618AT software provide high quality HD viewing at 1366x768 pixels in 720p (HD Ready). The input high-frequency or video signal is decoded in analog systems PAL, SECAM, NTSC. Graphic processing and formation of a digital signal occurs in the standards 480i, 480p, 576i, 576p, 720p, 1080i. Supported media file formats: MP3, WMA, MPEG4, MKV, JPEG. Stereo sound is provided by two built-in speakers. The NICAM STEREO audio processing system is used.
External interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, audio x2, component, VGA, HDMI x3, USB. To connect a computer or laptop to this TV model, use the VGA (D-Sub 15) connector on the TV case, this interface supports resolutions: 640x480, 800x600, 1024x768, 1360x768. The digital tuner is capable of receiving TV channels in DVB-T, DVB-T2 standards.
The TV uses a power supply unit as part of the MainBoard.
Dimensions: With stand 1057x662x210 mm, Without stand 1057x620x85 mm.
Attention! The LC320DXJ (SF) (E1) panel of the DNS K32D619 LED TV is an expensive and unreliable element.
Do not allow any impact on the glass and pressure on the screen surface to avoid damage to the LED panel!
It is also unsafe for liquid to spill onto the screen. Sometimes one drop is enough if it drips down the glass onto the cables to make the TV unrepairable.