Friday, 3 April 2020

REPAIR / SERVICING TV TOSHIBA 40RL838R

Technical description and composition of the TOSHIBA 40RL838R TV, type of panel and applicable modules. The composition of the modules.
TOSHIBA LED
Model: 40RL838R K
Chassis / Version: PE1014ZA
Panel: LTA400HM15
LED driver (backlight): SSL400 0E2C
PWM LED driver: SSL1005L
MOSFET LED driver: STA3250
Power Supply (PSU): N150A001L V71A00022900 rev02
PWM Power: A6069H (Standby), L6571, FAN6961 (PFC)
MOSFET Power: K12A50D
Mainboard: PE1014
IC MainBoard: TA55708 Sound
Tuner: ENGS7305D5F
Control: CT-90386
Specifications 40RL838
TOSHIBA 40RL838R
General repair guidelines for TV LCD LED
TOSHIBA 40RL838R K, like other televisions, it is advisable to start repairing with a careful examination of the external and internal elements and modules. According to some external signs of a change in the state of some elements, it is sometimes possible to make assumptions about the nature of the defect, as well as determine the further direction of the troubleshooting. In some cases, faulty elements can be seen with 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.
Sometimes the TOSHIBA 40RL838R TV simply does not turn on. No control lights on the front panel are lit or blinking, the TV does not respond to the remote control and does not make any sounds or any signs of life when turned on. The most likely cause of the malfunction is the failure of the Chicony V71A00022900 rev02 general power supply module. If it is working properly, you need to check the processor batteries on the SSB (Main Board). First of all, it is necessary to replace the swollen capacitors of the rectifier filters, if any. If the mains fuse is broken in the power supply, in most cases a breakdown of the power key (s) K12A50D is detected, which can be integrated with a PWM controller, or a separate field-effect transistor can be used. The rectifier bridge diodes and the electrolytic capacitor of the mains rectifier filter should also be checked.
It should be remembered that in the practice of repair, usually the power switches in switching power supplies (SMPS) do not fail due to their poor quality and, in such cases, it is necessary to look for the cause 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 A6069H PWM controller microcircuit may be faulty dezn b L6571B osnbp FAN6961 preconditioner. It is also necessary to check all the semiconductor elements of the stabilization circuit in the primary and secondary circuits.
If the TOSHIBA 40RL838R TV does not have an image, but there is sound, a malfunction in the LED backlight circuits of the LTA400HM15 panel is likely. It is also necessary to check the serviceability of the electrolytic capacitors of the filter of the secondary rectifiers of the PSU (power supply) for an overstated ESR.
To check the health of the LEDs, as well as contact connections in the ruler circuit, it is necessary to disassemble the panel.
It is impossible to detect a break in the LED line without disassembling the panel with a simple multimeter. The LEDs are connected in series and to open their transitions, a voltage of several tens of volts is required. Ideally, a current source is suitable for such purposes.
Board repair and replacement of chips TA55708 sound are made in the presence of the necessary equipment, and the corresponding element base. Faults associated with the application of BGA processor soldering technologies can be localized by the heating method.
If you suspect a malfunction of the ENGS7305D5F tuner, first of all, you need to make sure that the voltage of the varicaps (30-33V) is present on the corresponding output of the tuner, as well as other voltage supplying it.
Once again, we remind TV users: you should not make attempts to repair it yourself without the appropriate knowledge, experience and the necessary qualifications! Trust the repair only to professionals with sufficient experience in the field of electronic equipment repair.


SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    Toshiba 32RL838/RL858 Main: PE1014ZA schematic diagram



 The appearance of MainBoard PE1014 is shown in the figure below:
PE1014
PE1014 can be used in TVs:
TOSHIBA 32RL838R (Panel LTA320HN03 75027011), TOSHIBA 40RL838R K (Panel LTA400HM15).
PSU Advanced
According to the conditions of compliance with modern world standards for household switching power supplies, the N150A001L module provides for the use of a Power Factor Correction unit. The PFC circuit is a flyback converter based on the FAN6961 PWM controller. The reactance of an electrolytic capacitor of a line filter at a frequency of 50-60 Hz is usually not more than 20-30 ohms and its charge directly from the network through open diodes could reach tens of amperes per pulse if no filtering were applied.
As a result of the PFC conversion, an increased voltage on the capacitor (about 380V) cannot directly open the rectifier diodes, on the anode of which the voltage will always be slightly less (about 300V) and then its charging current will always be limited by the elements of the PWM controller. As a result, the envelope of the high-frequency pulses of the consumed current will repeat the shape and phase of the input sinusoidal voltage. The presence of an increased voltage (+ 380V) on the network capacitor indicates the serviceability of the PFC node.
The appearance of the power supply
Main features of the TOSHIBA 40RL838R device:
Installed matrix (LED-panel) LTA400HM15.
The LED driver SSL400 is used to power the backlight LEDs, it is controlled by the SSL1005L PWM controller. As power elements of the LED driver, keys of the STA3250 type are used.
The necessary supply voltages for all nodes of the TOSHIBA 40RL838R TV are generated by the N150A001L power module or its analogs using A6069H (Standby), L6571, FAN6961 (PFC) microcircuits and K12A50D type power switches.
MainBoard - the main board (motherboard) is a PE1014 module, using TA55708 sound chips and others.
The ENGS7305D5F tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: SAMSUNG
Model: LTA400HM15
Type: a-Si TFT-LCD, Panel
Diagonal size: 40 inch
Resolution: 1920x1080, FHD
Display Mode: SPVA, Normally Black, Transmissive
Active Area: 885.6x498.15 mm
Surface: Antiglare (Haze 0.5%), Hard coating (2H)
Brightness: 390 cd / m²
Contrast Ratio: 5000: 1
Display Colors: 1.07B (10-bit), CIE1931 72%
Response Time: 16 (Max.) (Tr + Td)
Frequency: 60Hz
Lamp Type: WLED Embedded (LED Driver)
Signal Interface: LVDS (2 ch, 10-bit), 51 pins
Voltage: 12.0V

 Trademark: TOSHIBA, Model: 40RL838.
Briefly from the TV: LCD, LED backlight, 40 ", 1920x1080, 1080p Full HD, sound: 20W, HDMI: 3, Internet access, Smart TV.
The composition uses MainBoard PE1014 and an LCD panel (matrix) LTA400HM15.
Power Supply Unit (PSU) N150A001L V71A00022900 rev02 Power Supply.
TOSHIBA 40RL838 LED TV with LTA400HM15 LCD display, 40 "(102 cm) diagonal size in 16: 9 format. The required screen brightness of 400 cd / m² is provided by LED backlighting. Dynamic contrast ratio of 3000000: 1 is achieved by special control of the LEDs. V This model uses side illumination from Edge LEDs.The design and technical capabilities of the TV include viewing programs and movies in high quality HD at a resolution of 1920x1080 pixels in a graphical resolution according to the standard 1080p (Full HD).
The 40RL838 is equipped with SMART software, integrated applications and the ability to work on the Internet. Connecting to the Internet can be done via Wi-Fi. The input high-frequency or video signal can be processed in analogue 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, Xvid, DivX, MKV, JPEG.
The power of the sound system 20 W (2x10 W) provides 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, SCART, RGB, VGA, HDMI x3, USB, Ethernet (RJ-45). 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, 1024x768, 1280x1024, 1360x768, 1920x1080.
A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C standards.
The power consumed by the TV in the operating mode from the network is 89 watts.
Overall dimensions: with stand 923x618x194 mm, without stand 923x562x57 mm.
Attention! The LTA400HM15 panel of the TOSHIBA 40RL838 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.