Monday 30 December 2019

REPAIR / SERVICING TV SAMSUNG QE55Q8CAM

Technical description and composition of the SAMSUNG QE55Q8CAM TV, panel type and applicable modules. The composition of the modules.
SAMSUNG LED
Model: QE55Q8CAM
Panel: CY-XM055FLLV1V
LED backlight: QLED Edge LED
T-CON: integrated into MainBoard
LED driver (backlight): BN44-00902A L65E8NC_MSM PSLF151E09C
Power Supply (PSU): BN44-00900A L55E8NA_MHS
MainBoard: BN41-02572A BN94-11487A
IC MainBoard: DAC: BURR BROWN 88002, AUDIO: TAS5747, DC / DC: VPM1RT
Tuner: SOC1000M BN95-03851A
Control: Remote: RMCRM1AP1, WIFI / BT: WCM730Q BN59-01264A
Technical Specifications QE55Q8CAM
SAMSUNG QE55Q8CAM
General repair guidelines for TV LCD LED
Possible malfunctions
- SAMSUNG QE55Q8CAM TV does not turn on. There are no signs of operability. The indicators on the front panel do not light or flash, the TV does not respond to the remote control and control buttons.
In some of these cases, the main switching power supply, the BN44-00900A module, is faulty. Then it is necessary to measure its output voltages and, in case of their complete or partial absence, it is necessary to check the serviceability of power switches and rectifier diodes of the converters for the presence of a possible short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during short circuit in the elements of the primary circuit, the mains fuse usually breaks.
The breakdown of power switches (MosFet) in pulsed sources is sometimes caused by malfunctions of other circuit elements, for example, in circuits supplying a PWM controller, frequency-setting or damper ones, as well as in negative feedback (OOS) stabilization circuits. PWM controllers (PWM), if they do not have visible damage to the chassis and open short circuit between the terminals, are usually checked by replacement.
- There is no image, there is sound, it responds to the remote control, the channels are switched. In some cases, the image appears when you turn on and immediately disappears.
As a rule, in such cases there is no display backlight. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
When trying to identify a break in the LED lines, it should be borne in mind that it is difficult to do this without disassembling the panel. For example, a current source is needed to open PN junctions connected in series.
- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the BN41-02572A motherboard should begin by checking the stabilizers and power converters needed to power the microcircuit and matrix. If necessary, you should update or replace the software (software). Complex repair of MB (SSB) is possible only in the conditions of a service center with the necessary equipment. Checking or replacing DAC elements: BURR BROWN 88002, AUDIO: TAS5747, DC / DC: VPM1RT requires the necessary training and professional skills to repair modules at the component level. Problems associated with the use of BGA soldering technologies can sometimes be diagnosed by warming up.
If there is no reception of television channels, but the TV is working properly from external devices, first of all you need to check the voltage of the SOC1000M BN95-03851A tuner and update the software. The pulses from the I2C bus must be controlled with an oscilloscope.
We recommend the owners of the QE55Q8CAM TV for repair only to qualified specialists with the necessary work experience! Attempts to repair it yourself without the appropriate knowledge and skills can lead to irreversible negative consequences!



The appearance of the MainBoard BN41-02572A is shown in the figure below:
BN41-02572A
The appearance of the power supply
Main features of the SAMSUNG QE55Q8CAM device:
Installed matrix (LED panel) CY-XM055FLLV1V.
The matrix control uses the Timing Controller (T-CON) integrated.
The LED driver BN44-00902A is used to power the backlight LEDs.
The formation of the necessary supply voltages for all nodes of the SAMSUNG QE55Q8CAM TV is carried out by the BN44-00900A power module, or its analogues.
MainBoard - the main board (motherboard) is a BN41-02572A module, using DAC chips: BURR BROWN 88002, AUDIO: TAS5747, DC / DC: VPM1RT and others.
Tuner SOC1000M BN95-03851A provides the reception of television programs and tuning to channels.