Sunday 19 April 2020

REPAIR / SERVICING TV DEXP F49C8000H

Technical description and composition of the DEXP F49C8000H TV, type of panel and applicable modules. The composition of the modules.
DEXP LED
Model: F49C8000H
Chassis / Version: RSAG7.820.6526
Panel: HV490FHB-N80 Rev.1.0 HD490DF-B71 / S7 / GM
LED backlight: Hisense 49 HD490DF-B71 4X10 3030C V0
T-CON: 47-6021064 49 GOA Tcon Board
LED driver (backlight): integrated into PSU
Power Supply (PSU): RSAG7.820.5687 / ROH HLL-4855WP
PWM Power: NCP1271, NCP1608
MOSFET Power: 10N60, 8N65
MainBoard: RSAG7.820.6526 / ROH HX49K3120FWT
IC MainBoard: H26M31001HPR Hynix
Control: WiFi: WN4640R_V01 323K246021YD
Technical Specifications F49C8000H
DEXP F49C8000H
General repair guidelines for TV LCD LED
Possible malfunctions
- The DEXP F49C8000H TV does not turn on and does not show any signs of turning on, it does not respond to the control buttons or the remote control.
In such cases, the RSAG7.820.5687 power supply is usually faulty. It is necessary to measure its output supply voltage, and in case of their absence, check the serviceability of the power switches (10N60, 8N65) of the converters and rectifier diodes for the probability of breakdown in PN semiconductor junctions.
In case of breakdowns in the secondary circuits of the converter, it can usually fail in short circuit mode, and in case of a short circuit in the power elements of the primary circuit, the mains fuse or current sensor at the source of the key most often 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. These can be circuits supplying the PWM controller, damping or frequency-setting circuits, or elements of OOS (negative feedback) in the stabilization circuit. PWM controllers (PWM) NCP1271, NCP1608, in the absence of external damage and short circuit between the terminals, are checked by replacing with obviously good ones.
- There is no image, there is sound, it responds to the remote control. Or the image may appear for a second when turned on and immediately disappears.
The most likely in these cases is a malfunction of the LED backlight. The reason can 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 detect a break in the LED lines without disassembling the panel, a current source is required. It is impossible to open transitions connected in series with a simple multimeter; voltage of several tens of volts is necessary.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the RSAG7.820.6526 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). In some cases, to repair the MB board (SSB), it may be necessary to replace the chips - H26M31001HPR Hynix with new or obviously good ones. In cases where BGA technologies are used, defects are usually localized by the heating method.
Attention! For users and owners of F49C8000H TVs who do not have the appropriate qualifications, knowledge and experience, we strongly recommend against attempting self-repair in order to avoid negative consequences that could lead to complete non-repairability of the device.





The appearance of the MainBoard RSAG7.820.6526 is shown in the figure below:
RSAG7.820.6526
The appearance of the power supply
Main features of the DEXP F49C8000H device:
Installed matrix (LED-panel) HV490FHB-N80 Rev.1.0 HD490DF-B71 / S7 / GM.
The matrix control uses the Timing Controller (T-CON) 47-6021064.
To power the backlight LEDs, a converter is used, combined with a power supply.
The necessary supply voltages for all nodes of the DEXP F49C8000H TV are generated by the RSAG7.820.5687 power module or its analogs using NCP1271, NCP1608 microcircuits and 10N60, 8N65 type power switches.
MainBoard - the main board (motherboard) is an RSAG7.820.6526 module, using H26M31001HPR Hynix chips and others.
DEXP F49C8000H TV with HV490FHB-N80 LCD, 49 "(124 cm) diagonal size of 16: 9 format. The required screen brightness of 275 cd / m² is provided by LED backlighting. Contrast - the ratio of maximum brightness to minimum is 1000: 1. The LCD panel uses direct pixel illumination with rear LEDs - Direct LED.The TV features include viewing programs and movies in high quality HD at a resolution of 1920x1080 pixels in the graphic resolution of the standard 1080p (Full HD).
The F49C8000H is equipped with SMART software, embedded applications and the ability to work on the Internet. Connecting to the Internet can be done via Wi-Fi. Supported media file formats: MP3, WMA, MPEG4, DivX, MKV, JPEG.
The power of the sound system 16 W (2x8 W) provide two speakers. It uses a NICAM stereo signal processing system and Sound Surround.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, component, HDMI x3, MHL, USB x2, Ethernet (RJ-45), Wi-Fi. An output for connecting headphones is provided. A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
The power consumed by the TV working in the network mode is 115 watts.
Overall dimensions: with stand 1099x691x246 mm, without stand 1099x639x85 mm.
TV Weight: with stand: 12.1 kg, without stand: 11.9 kg.
Attention! The HV490FHB-N80 Rev.1.0 HD490DF-B71 panel of a DEXP F49C8000H 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.