Technical description and composition of the SITRONICS LCD-2021 TV, type of panel and applicable modules. The composition of the modules.Sitronics
Model: LCD-2021
Chassis / Version: JUJ7.820.135
Panel: 20 inch
Power Supply (PSU): Adapter 12V
MainBoard: JUJ7.820.135
IC MainBoard: TDA15063H / N1B00 MST518 24LC32
Tuner: TAF5-C2IP1RW
Appearance
SITRONICS LCD-2021
General repair guidelines for TV LCD
It is advisable to start any repair and diagnostics of the Sitronics LCD-2021 TV with a careful external examination of internal and external elements, including case parts, a display, buttons and cables. Often, for certain external signs, the repairman can draw some conclusions about the reasons for the failure of certain elements of the circuit even before the necessary measurements are made, which will determine the further algorithm for troubleshooting and localizing the defect. In most cases, the repairman can guess the causes of the defect and possible consequences by the characteristic signs of typical TV defects, for example, ring cracks formed in the soldering of the element leads, swollen rectifier filter capacitors, charred resistors and other circuit elements.
In the absence of any signs of operability, when the Sitronics LCD-2021 does not turn on and does not signal anything with the control lights on the panel, the power module is most likely faulty. When diagnosing and repairing the power supply, first of all, it is necessary to check the fuse and, if it is broken, it is necessary to identify the cause. Often in such cases, an avalanche (thermal) breakdown is detected in the power semiconductor elements of the module - rectifier diodes or power key.
The reasons for the breakdown of the power switch of the flyback converter of the power module can be different, for example, a malfunction of semiconductor cells or electrolytic capacitors in the stabilization circuits of the primary circuit, as well as a failure in the operation of the PWM controller chip or breakage of the resistors in its bundle.
In cases using a power module with an active KKM, troubleshooting is sometimes somewhat more complicated.
If the Sitronics LCD-2021 does not have an image, there is sound and the channels are switched, there is a possibility of a malfunction of the display backlight, or their power converter - inverter. Sometimes when you turn on the image appears and disappears immediately. In such cases, it is necessary to check the electrolytic capacitors of the power filter of the inverter itself, including in the secondary rectifier of the main PSU.
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 to be able to make the necessary measurements at the control points of the circuit.
It should be remembered that when the protection is turned off, there is always a risk of failure of the inverter power elements during diagnosis. After repair, it is necessary to restore all standard converter protection circuits.
Repair or diagnostics of the motherboard should be started by checking the power stabilizers. If necessary, update the software (software). In cases of complex repairs of MB (SSB) and in the presence of the necessary skills and equipment, sometimes it may be necessary to replace its chips TDA15063H / N1B00 MST518 24LC32, Tuner: TAF5-C2IP1RW and other possible faulty components.
Owners and users of the Sitronics LCD-2021 TV must remember that self-repair without special knowledge, skills and qualifications can be fraught with negative consequences that can lead to complete non-repairability of the device!
SCHEMATIC DIAGRAM / SERVICE MANUAL ------------------> SITRONICS LCD-2021
Main technical specifications:20-inch diagonal, Resolution 640x480, 4: 3, Brightness 450 cd / m2, Contrast 350: 1, Viewing angle 176 °
Repair MainBoard
The appearance of the MainBoard JUJ7.820.135 is shown in the figure below:
JUJ7.820.135
Main features of the SITRONICS LCD-2021 device:
Installed matrix (LCD-panel) 20 inches.
To power all the internal components of the SITRONICS LCD-2021 TV, an external adapter 12V type is used.
MainBoard - the main board (motherboard) is a JUJ7.820.135 module, using TDA15063H / N1B00 MST518 24LC32 chips and others.
The TAF5-C2IP1RW tuner provides TV reception and channel tuning.