Technical description and composition of the SAMSUNG LE40R81 TV, panel type and applicable modules. The composition of the modules.SAMSUNG
Model: LE40R81
Chassis / Version: BP40EO
Panel: LTA400WT-L06 (L09)
Inverter (backlight): SSB400WA16v Rev0.1
PWM Inverter: LX1691A
MOSFET Inverter: 2SK3568
Trans Inverter: BL-1040 (16 lights)
Power Supply (PSU): BN44-00167A
PWM Power: ICE1PCS02 (PFC), ICE3B0365J, FSDM0565
MOSFET Power: FQA13N50CF (PFC)
MainBoard: BN41-00839B
Tuner: BN40-00078A
Control: BN59-00602A
Technical Specifications LE40R81B
SAMSUNG LE40R81
General repair guidelines for TV LCD
SAMSUNG LE40R81 TV, like any other, it is advisable to start repairing with an examination of internal and external elements. Visible damage to elements can sometimes suggest directions for finding a defect even before the necessary measurements are taken. In some cases, faulty elements are visible to the naked eye, for example, charred resistors or swollen metal-ceramic capacitors, or electrolytic in rectifier filters. Ring cracks formed in the soldered terminals of transformers or heating elements of the circuit are also frequent sources of many malfunctions with a variety of external manifestations.
If the TV does not turn on, no indicators on its front panel are lit or blinking. Also, if the TV does not respond to the remote control and buttons, does not make any sounds or any signs of operability when turned on, there is a certain chance that the BN44-00167A power supply module is defective and needs repair. Sometimes with similar manifestations, a problem can only occur in the absence of processor power, but this happens much less often. In this case, first of all, it is necessary to check the fuse at the mains input. If it is broken, then you should check for breakdown of the PN junctions of the rectifier bridge diodes and the key transistor of the N-FET converter, which can either be on a separate radiator or integrated with a PWM controller in a common chip. Possible options.
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 reason 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.
When using a power factor correction unit (PFC) in the power modules, troubleshooting becomes somewhat more complicated and requires additional experience and knowledge of the device for their operation.
In those cases when the SAMSUNG LE40R81 TV has lost its image, and the sound is there and all the other functions are operational, there is a possibility of a malfunction of the inverter (converter for powering the backlight). When you turn on the TV, the image may appear briefly and immediately disappear. It must be borne in mind that with such manifestations, the lamps themselves also fail, the malfunction of which can be detected by replacement, by connecting to the connectors for diagnostics that are known to be serviceable and suitable in power.
In most cases, the diagnosis and repair of the SSB400WA16v Rev0.1 inverter is difficult due to the organization of protection, which turns it off in emergency cases to avoid fires during short circuits or open circuits in high voltage circuits and during depressurization of lamps. Often, repairmen block the protection circuits in order to make the necessary measurements at the control points of the inverter to identify the causes of the defect.
All necessary precautions must be observed when disabling the inverter protection during diagnostics and not leaving it disconnected after the repair is completed.
In cases of attempts to repair the motherboard BN41-00839B, it is necessary to check the operability of the power stabilizers of the microcircuits and, if possible, update the software (software).
It should be remembered! Attempts to repair the SAMSUNG LE40R81 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!
PSU SCHEMATICS --------> Samsung BN44-00167A Power supply.
The appearance of the MainBoard BN41-00839B is shown in the figure below:BN41-00839B
BN41-00839B can be used in TVs:
SAMSUNG LE37R81B (Panel T370XW02 V.5), SAMSUNG LE40R81 (Panel LTA400WT-L06 (L09)).
PSU Advanced
The LE40R81 TV is equipped with a BN44-00167A power module using the PFC (Power Factor Correction) scheme acting as an active filter to eliminate the higher harmonic components of the current consumption. The boost converter based on the ICE1PCS02 PWM controller does not allow the input rectifier filter's electrolytic capacitor to be connected to the network directly through open diodes when the charge current determines its reactance (about 15-30 ohms at a frequency of 50 Hz). As a result of the conversion, the charging current of the capacitor will be determined in such a way that the envelope of the high-frequency pulses of the input current will repeat the phase and shape of the sine wave of the input voltage. The health check of the PFC unit is carried out by measuring the DC voltage on the capacitor of the rectifier network. In operating mode, it should be around 380V, in standby approximately 300V.
The appearance of the power supply
Main features of the SAMSUNG LE40R81 device:
Installed matrix (LCD panel) LTA400WT-L06 (L09).
To power the backlight, an SSB400WA16v inverter is used, it is controlled by the LX1691A PWM controller. A transformer BL-1040 (16 lamps) is installed in the inverter converter. As power elements of the inverter, keys of the 2SK3568 type are used.
The necessary supply voltages for all nodes of the TV SAMSUNG LE40R81 are formed by the power module BN44-00167A, or its analogs using ICE1PCS02 (PFC), ICE3B0365J, FSDM0565 microcircuits and power switches of the FQA13N50CF (PFC) type.
MainBoard - the main board (motherboard) is a BN41-00839B module.
The tuner BN40-00078A provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: SAMSUNG
Model: LTA400WT-L06
Type: a-Si TFT-LCD, Panel
Diagonal size: 40 inch
Resolution: 1366x768, WXGA
Display Mode: S-PVA, Normally Black, Transmissive
Active Area: 885.168x497.664 mm
Surface: Antiglare (Haze 40%), Hard coating (3H)
Brightness: 600 cd / m²
Contrast Ratio: 2000: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 10/6 (Tr / Td); 8 (G to G)
Frequency: 60Hz
Lamp Type: 16 pcs CCFL Embedded (Balance board)
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V