Technical description and composition of the SITRONICS LCD-2770 TV, type of panel and applicable modules. The composition of the modules.Sitronics
Model: LCD-2770
Panel: V270B1-L01
MainBoard: GLK7.820.004-J02
IC MainBoard: CPU: VCT40X3R F2 000; Eeprom: 24C64, 24c08
Tuner: KSH-148DEA
Appearance
SITRONICS LCD-2770
General repair guidelines for TV LCD
It is advisable to start any repair and diagnostics of the Sitronics LCD-2770 TV with a careful external examination of internal and external elements, including case parts, a display, buttons and cables. Often, according to the external signs and the nature of some damage, it is possible to draw preliminary conclusions and determine a further algorithm for finding and localizing a malfunction. Swollen electrolytic or cermet capacitors, charred resistors, ring cracks in the soldered terminals of the elements - all this can significantly help the master to determine the causes and consequences of the malfunction of the TV.
In cases where the Sitronics LCD-2770 TV does not turn on, does not respond to the remote control and buttons, no indicators on the front panel light up or blink, and there are no sounds and no signs of operability when turning on, the power module is most likely faulty or, what it happens much less often - there is no processor power on the motherboard. It is advisable to start the troubleshooting of the power supply module by checking the mains fuse. If it is torn, it is necessary to check first of all the power semiconductor elements - rectifier diodes and the power switch of the converter, which are often found in breakdown conditions in such situations.
It should be remembered that in the practice of repair, usually the power keys of N-Fet converters do not fail due to their poor quality and, in such cases, it is necessary to look for the cause that led to a malfunction and provoked a breakdown of the key. Most often, the culprits of the accident are dried electrolytic capacitors or dangling resistors in the primary circuit, or the PWM controller chip itself may be faulty. It is also necessary to check all the semiconductor elements of the stabilization circuit in the primary and secondary circuits.
If an active Power Factor Corrector (CMC) is used in the power module circuitry, it is sometimes more difficult to troubleshoot. Knowledge, experience, intuition and skills in such cases have a great advantage for a successful repair.
If the Sitronics LCD-2770 does not have an image, but there is sound and the TV is controlled from the remote control, a malfunction in the display backlight nodes is likely. The lamps or the power converter - inverter may be faulty. Often in such cases, when you turn on the TV, an image appears and immediately disappears. First of all, it is necessary to verify the operability of the electrolytic capacitors of the rectifier filter supplying the inverter, and check the LCD lamps by connecting external and obviously serviceable for diagnosis to the connectors.
Repair of the inverter can often be somewhat complicated by the use of special protection circuits, which are designed to disconnect it in emergency cases for fire safety during depressurization of lamps, or short circuits or breaks in high-voltage circuits and connections. Sometimes it becomes necessary for diagnostic purposes to block the protection circuits in order to be able to make the necessary measurements at the control points of the circuit.
Turning off the protection for diagnostic purposes, it must be remembered that in this case there is a risk of failure of the power elements of the inverter. Upon completion of the diagnosis, all regular protection circuits should be restored.
It should be remembered! Attempts to repair the Sitronics LCD-2770 TV, in the absence of the necessary qualifications and experience, are categorically not recommended and are fraught with negative consequences, up to the complete non-repairability of the device!
The scheme for Sitronics TVs, lcd-2070, lcd-2770, lcd-3270 models can be downloaded here:
SCHEMATIC DIAGRAM / SERVICE MANUAL ------------------> lcd_2070_2770_3270.rarMain features of the SITRONICS LCD-2770 device:
Installed matrix (LCD panel) V270B1-L01.
The required supply voltage for all nodes of the SITRONICS LCD-2770 TV is provided by a switching power supply.
MainBoard - the main board (motherboard) is a module GLK7.820.004-J02, using CPU chips: VCT40X3R F2 000; Eeprom: 24C64, 24c08 and others.
The KSH-148DEA tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: CMO
Model: V270B1-L01
Type: a-Si TFT-LCD, Panel
Diagonal size: 27.0 inch
Resolution: 1366x768, WXGA
Display Mode: Super MVA, Normally Black, Transmissive
Active Area: 596.259x335.232 mm
Surface: Antiglare, Hard coating (3H)
Brightness: 550 cd / m²
Contrast Ratio: 1000: 1
Display Colors: 16.7M (8-bit), CIE1931 75%
Response Time: 8 (G to G)
Frequency: 60Hz
Lamp Type: 14 pcs CCFL Embedded (Inverter)
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 5.0V