Wednesday, 22 July 2020

REPAIR / SERVICING TV SUPRA STV-LC2642

Technical description and composition of the SUPRA STV-LC2642 TV, panel type and modules used. The composition of the modules.
SUPRA
Model: STV-LC2642
Chassis / Version: LC-26-37HU26S
Panel: V260B1-L01
MainBoard: 782.GHU25-010D
IC MainBoard: CPU: MST9E88L; DRAM: HY5DU281622ET; SPI Flash: PM25VF040; EEPROM: 24C32; SOUND: MP7722DF;
Tuner: TDQ-6F6 / W124X
Appearance
SUPRA STV-LC2642
General recommendations for TV LCD repair
It is advisable to start repairing a SUPRA TV with a chassis with a careful external examination of both internal and external elements. Visible damage to elements can sometimes indicate the direction of searching for a defect even before the necessary measurements are taken. In some cases, defective elements are visible to the naked eye, for example, charred resistors or swollen sintered capacitors, or electrolytic ones in rectifier filters. The formed ring cracks in the soldering of the terminals of transformers or heating circuit elements are also frequent sources of many malfunctions with a variety of external manifestations.
If the power supply module fails, external manifestations may be different, for example, SUPRA STV-LC2642 does not turn on at all and there is no indication of the control lamps on the front panel. With the same symptoms, the regulator (converter) of the control processor power supply may be faulty. When diagnosing and repairing the power supply, after replacing the swollen capacitors of the secondary rectifier filters (if any), you must first check the mains fuse. If it breaks, the power elements of the transistors and diodes of the rectifier bridge should be checked for avalanche (thermal) breakdown.
If a breakdown of the power switch is detected, it should be remembered that in a switching power supply (SMPS) it does not fail by itself without reasons that should be looked for by checking other elements of the primary circuit - electrolytic capacitors, a PWM controller, which can only be checked replacement, as well as other semiconductor elements (diodes, transistors, zener diodes).
If, when SUPRA STV-LC2642 is turned on, there is no image, or it appears for a second and disappears completely, but there is sound, most likely either the backlight lamps or their power converter (inverter) are faulty. It is necessary to check the electrolytic capacitors of the filter of the secondary rectifiers in the common power supply.
The operation of the power circuits of the inverter and the backlight lamps in the normal mode is controlled by special protection, which is organized for fire safety purposes, for example, for shutdown when short circuits or breaks in high-voltage connections or when lamps are depressurized. This protection makes it difficult to diagnose and repair the inverter.
Owners of the STV-LC2642 TV are advised to contact only qualified specialists with experience for repair! Attempts to repair yourself without the appropriate knowledge and skills can lead to serious negative consequences!

SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    SUPRA STV-LC3742  CHASSIS: LC-(26-37)HU26S


 The appearance of the MainBoard T.MS6M48.7A is shown in the figure below:
T.MS6M48.7A
T.MS6M48.7A can be used in TVs:
SUPRA STV-LC3244FL (Panel 1080p Full HD 1920x1080), SUPRA STV-LC2625WL (Panel TC260B306), SUPRA STV-LC3225WL (Panel TC315B601), SUPRA STV-LC2644WL (Panel T260XW06 V.4), SUPRA STV-LC4225AFL (Panel TC420F115), SUPRA STV-LC3225LF (Panel V315H4-LE2).
Main features of SUPRA STV-LC2642 device:
Installed matrix (LCD panel) V260B1-L01.
The required supply voltages for all nodes of the SUPRA STV-LC2642 TV are provided by a switching power supply.
MainBoard - the main board (motherboard) is a 782.GHU25-010D module, using CPU chips: MST9E88L; DRAM: HY5DU281622ET; SPI Flash: PM25VF040; EEPROM: 24C32; SOUND: MP7722DF; and others.
The TDQ-6F6 / W124X tuner provides reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: CMO
Model: V260B1-L01
Type: a-Si TFT-LCD, Panel
Diagonal size: 26.0 inch
Resolution: 1366x768, WXGA
Display Mode: TN, Normally White, Transmissive
Active Area: 575.769x323.712 mm
Surface: Antiglare (Haze 25%), Hard coating (3H)
Brightness: 500 cd / m²
Contrast Ratio: 800: 1
Display Colors: 16.2M (6-bit + FRC), CIE1931 72%
Response Time: 3/5 (Tr / Td)
Frequency: 60Hz
Lamp Type: 12 pcs CCFL Embedded (Inverter)
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 5.0V