Technical description and composition of the DEXP F55B7200C TV, type of panel and applicable modules. The composition of the modules.DEXP LED
Model: F55B7200C
Panel: C550F14-E6-L
T-CON: T-CON: V15 FND DRD P / N: 6870C-0532B; TL2375EP, RT6919C, T08 (TSSOP-8)
LED driver (backlight): with integrated PSU
Power Supply (PSU): MP145D-1MF22 REV: 1.0
PWM Power: UCC28019A, L6599D (PWM Push-Pull), AS358A
MOSFET Power: MDF18N50B, MDF5N50F X2, JCS4N65FB
MainBoard: JUC7.820.00125910
IC MainBoard: 25Q32C, TPS54428 IAGMF, (SOT23-6), RT9108NB
Tuner: CH DMI21-C8I6RH
Technical Specifications F55B7200C
DEXP F55B7200C
General repair guidelines for TV LCD LED
Possible malfunctions
- DEXP F55B7200C does not turn on and does not show any signs of operability. Does not blink indicators and does not respond to any control buttons.
With such manifestations, a malfunction is most likely to be detected in the MP145D-1MF22 power supply module. It is necessary to measure the secondary output voltage, and in case of their absence, check the health of the power switches (MDF18N50B, MDF5N50F X2, JCS4N65FB) of converters and rectifier diodes for a short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during a short circuit in the elements of the primary circuit, the mains fuse usually breaks.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke an excess of the maximum current or voltage. It can be supply, damper circuits, or elements of OOS (negative feedback) stabilization. The reason for the breakdown of the power key may be PWM (PWM) UCC28019A, L6599D (PWM Push-Pull), AS358A. It is checked only by replacement with a known good one.
- There is no image, there is sound, it is responding to the remote control. Or immediately after turning on for a second, the image may appear and immediately disappear.
Usually in such cases, a malfunction is detected in the backlight nodes of the LED panel. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
To check the LED strips, 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 transitions in forward bias, you can sometimes detect the presence of a PN junction of the protective zener diode by connecting the probes in the opposite direction. If the zener diode is broken or broken in short-circuit, then the LED is faulty and needs to be replaced.
- The TV does not enter the operating mode, does not respond to the remote control. The indicator on the front panel lights constantly or blinks.
Repair or diagnostics of the JUC7.820.00125910 motherboard should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (software). Sometimes it is necessary to check or replace (if necessary) the elements of the MainBoard - 25Q32C, TPS54428 IAGMF, (SOT23-6), RT9108NB. In cases where the BGA processor is used, its malfunction is usually detected by local heating.
In the absence of tuning to the channels of on-air or cable television, you should make sure that the software is correct, as well as in accordance with the ratings of the supply voltage at the terminals of the tuner CH DMI21-C8I6RH. It is also necessary to check the presence of pulses of data exchange between the tuner and the processor via the I2C bus using an oscilloscope.
Attention! Users and owners of F55B7200C televisions who do not have the appropriate qualifications, knowledge and experience are strongly advised against self-repair attempts in order to avoid negative consequences that could lead to complete non-repairability of the device.
DEXP F55B7200C Service Mode: SOURCE - 3 - 1 - 3 - 8. First turn on the TV by selecting the DTV source, wait 20 seconds, then dial this combination without haste. It does not always work the first time. If it does not work, click EXIT and a new one.
The appearance of the MainBoard JUC7.820.00125910 is shown in the figure below:JUC7.820.00125910
JUC7.820.00125910 can be used in TVs:
DEXP F55B7200C (Panel C550F14-E6-L), DEXP F43B7200C (Panel C430F14-E1-L).
The appearance of the power supply
Main features of the DEXP F55B7200C device:
Installed matrix (LED panel) C550F14-E6-L.
The matrix control uses the Timing Controller (T-CON) T-CON: V15.
To power the backlight LEDs, a converter is used, combined with a power supply.
The necessary supply voltages for all nodes of the DEXP F55B7200C TV are generated by the MP145D-1MF22 power supply module or its analogs using UCC28019A, L6599D (PWM Push-Pull), AS358A microcircuits and power switches of the MDF18N50B, MDF5N50F X2, JCS4N65FB type.
MainBoard - the main board (motherboard) is a JUC7.820.00125910 module, using 25Q32C, TPS54428 IAGMF, (SOT23-6), RT9108NB and others.
The CH DMI21-C8I6RH tuner provides TV reception and channel tuning.
DEXP F55B7200C TV with C550F14-E6-L LCD, 55 "(140 cm) diagonal size of 16: 9 format. The required screen brightness of 350 cd / m² is provided by LED backlighting. Contrast - the ratio of maximum brightness to minimum is 1200: 1. The LCD panel uses direct backlighting of pixels with a rear LED arrangement - Direct LED.The TV features include viewing programs and movies in high quality HD at a resolution of 1920x1080 pixels in a graphic resolution of 1080p (Full HD) standard. Input high-frequency or video The signal is decoded in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats: MP3, WMA, MPEG4, MKV, JPEG.
The power of the acoustic system of sound 20 W (2x10 W) provide two speakers. The audio processing system NICAM STEREO is used.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, component, VGA, HDMI x3, USB. An output for connecting headphones is provided. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector is used on the TV case, this interface supports resolutions: 640x480, 800x600, 1360x768, 1920x1080. A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
Overall dimensions: with stand 1250x780x240 mm, without stand 1250x720x90 mm.
TV Weight: with stand: 13.8 kg, without stand: 12 kg.
Attention! The C550F14-E6-L panel of a DEXP F55B7200C LED TV is an expensive and unreliable element.
Avoid any impact on the glass and pressure on the surface of the screen to avoid damage to the LED panel!
It is also unsafe to get liquid on the screen. Sometimes one drop is enough if it flows down the glass onto the cables so that the TV becomes unrepairable.
