Wednesday, 2 September 2020

REPAIRING / SERVICING TV GOLDSTAR LT-22A300F


Technical description and composition of the GOLDSTAR LT-22A300F TV, panel type and modules used. The composition of the modules.
GoldStar LED
Model: LT-22A300F
Chassis / Version: CV181L-Y
Panel: M215HGE-P02
T-CON: M215HGE-L21-X + C
LED driver (backlight): integrated into PSU
PWM LED driver: OB3362RP
Power Supply (PSU): HKC-PL01 REV.3.0
PWM Power: SG6848 (PWM SOT23-6 AExxx)
MOSFET Power: 7N65
MainBoard: CV181L-Y
IC MainBoard: 25Q32BVS1G, X5DV330, U4-AS7805D, RT8296AH, 1517P
Tuner: CDT-3SP512-37
Control: IR: 6003120090 19-42V3-IR-V2.0.PCB
LT-22A300F Specifications
GOLDSTAR LT-22A300F
General recommendations for TV LCD LED repair
Possible manifestations of malfunctions
- The GoldStar LT-22A300F TV does not turn on and does not show any signs of operability at all. No response to the remote control and front panel control buttons.
In some of these cases, the main switching power supply, the HKC-PL01 module, is faulty. In the absence of the necessary supply voltages in the secondary circuits of the converters, it is necessary to check the power switches (7N65) and rectifier diodes for possible partial or complete breakdown.
In case of any breakdown of semiconductors in the secondary circuits, the converter can usually operate normally in an emergency short-circuit mode. There are no output voltages. And with a short circuit in the power elements of the primary circuit, as a rule, the mains fuse breaks and, less often, the current sensor in the source of the key.
Mos-Fet power switches used in switching power supplies sometimes fail due to a malfunction of any other elements that can disable it in the key mode, or create an excess of the maximum permissible key parameters. These can be elements supplying a PWM regulator, frequency setting or damper circuits, or elements of negative feedback in the stabilization circuit. PWM controllers SG6848 (PWM SOT23-6 AExxx), in the absence of visible damage or outright short circuits between the terminals, are checked by replacing them with new ones, or known to be working properly.
- There is no picture, but there is sound and reaction to commands from the remote control. Or the image appears immediately after switching on and disappears.
The malfunction in most of these cases is found in the nodes and elements of the LED panel backlight. 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 TV does not turn on, the indicator signals the standby or operating mode, or blinks.
Repair or diagnostics of the CV181L-Y motherboard should begin with checking the stabilizers and power converters necessary to power the microcircuits and matrix. If necessary, you should update or replace the software (software). In some cases, to repair the MB (SSB) board, it may be necessary to replace the chips - 25Q32BVS1G, X5DV330, U4-AS7805D, RT8296AH, 1517P with new or known good ones. In cases where BGA technologies are used, defects are usually localized by heating.
If you suspect a malfunction of the CDT-3SP512-37 tuner, first of all you need to make sure that the software is correct, as well as the presence of the required levels of supply voltages and pulses of data exchange with the processor via the I2C bus on the corresponding terminals of the tuner.
Attention to users! Self-repair of the GoldStar LT-22A300F TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!

To reduce the backlight current in LED drivers with OB3362RP (TSOP16) controller, increase the total resistance of the resistors from pin 5 (ISET) to the case. The maximum current in each of the four channels (in milliamperes) for the Rset resistor (in kilo-ohms) is determined from the ratio 3000 * 1.2V / Rset.
Additional MainBoard Repair
The appearance of the MainBoard CV181L-Y is shown in the figure below:
The CV181L-Y motherboard uses the MST6M181VG processor, combined with a scaler and installed using the BGA technology.
It is advisable to start repairing this MainBoard with checking the linear stabilizers and voltage converters required to provide power to the processor units: 1.2V, 2.5V, 3.3V. If there is no image, but the display backlight is in good condition, it is necessary to check the power supply of the LCD panel 5V or 12V, depending on the type of panel used, which is advisable to measure directly on the LVDS connector.


 It is advisable to start repairing this MainBoard with checking the linear stabilizers and voltage converters required to provide power to the processor units: 1.2V, 2.5V, 3.3V. If there is no image, but the display backlight is working properly, it is necessary to check the power supply of the LCD panel 5V or 12V, depending on the type of panel used, which is advisable to measure directly on the LVDS connector. If, with the necessary supply voltages, the TV does not come out of Stand-by mode, does not respond to the remote control and control buttons, you should update the SPI Flash software.
https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4KzY6L0tB6Byw6kCRFx-f3ZyMG2uqNMdD7s4eLibQaADQzq_iLfO1zD-1YxtGTRfJGZ-71_dteeQIqbt6U34A2C6yn-U5umIQR82bLjHsVMDWMvC9HfPWwjtvlP8hpoZmVBTW5m0LyNQ/s1600/HKC-PL01_DCE.jpgCV181L-Y can be used in TVs:
FUSION FLTV-19L16B (Panel M185B3-PA1), SUPRA STV-LC1977WLD (Panel M185BGE-P02), SUPRA STV-LC2477FLD (Panel HK236WLEDM-IH61H), THOMSON T22E32HU (Panel LM215WF4 (TL)(E7)).
External view of the power supply
Main features of the GOLDSTAR LT-22A300F device:
Installed matrix (LED-panel) M215HGE-P02.
Matrix control uses Timing Controller (T-CON) M215HGE-L21-X + C.
To power the backlight LEDs, a converter combined with a power supply is used, controlled by the OB3362RP PWM controller.
The formation of the necessary supply voltages for all nodes of the GOLDSTAR LT-22A300F TV is carried out by the HKC-PL01 power module, or its analogs using SG6848 microcircuits (PWM SOT23-6 AExxx) and power switches of the 7N65 type.
MainBoard - the main board (motherboard) is a CV181L-Y module, using microcircuits 25Q32BVS1G, X5DV330, U4-AS7805D, RT8296AH, 1517P and others.
The CDT-3SP512-37 tuner provides reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: CHIMEI INNOLUX
Model: M215HGE-P02
Type: a-Si TFT-LCD, CELL
Diagonal size: 21.5 inch
Resolution: 1920x1080, FHD
Display Mode: TN, Normally White, Transmissive
Active Area: 476.64x268.11 mm
Surface: Antiglare (Haze 25%), Hard coating (3H)
Transmissivity: 6.3% (with Polarizer)
Contrast Ratio: 1000: 1
Display Colors: 16.7M (8-bit)
Response Time: 1.5 / 3.5 (Tr / Td)
Frequency: 60Hz
Signal Interface: LVDS (2 ch, 8-bit), 30 pins
Voltage: 5.0V
GOLDSTAR LT-22A300F TV with LCD M215HGE-P02, 22 "(56 cm) diagonal, 16: 9 format. The required screen brightness of 250 cd / m² is provided by LED backlighting. Dynamic contrast ratio of 60,000: 1 is achieved by special control of LED operation The LED panel of this TV is equipped with Edge LED backlighting.The design and technical capabilities of the TV provide viewing of broadcasts and movies in high quality HD at a resolution of 1920x1080 pixels in graphic resolution according to the standard 1080p (Full HD) .Input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC Graphic processing and digital signal shaping takes place in 480i, 480p, 576i, 576p, 720p, 1080i, 1080p standards.
The power of the sound system is 6 W (2x3 W), provided by two 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, SCART, VGA, HDMI. A headphone output is provided. 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 power consumed by the TV operating in mains mode is 40 W.
Overall dimensions: 526x377x155 mm.
TV weight: 3.48 kg.
Attention! Panel M215HGE-P02 LED TV GOLDSTAR LT-22A300F 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.