Saturday 4 April 2020

REPAIR / SERVICING TV TOSHIBA 42HL834R

Technical description and composition of the TOSHIBA 42HL834R TV, type of panel and applicable modules. The composition of the modules.
TOSHIBA LED
Model: 42HL834R
Panel: LC420EUN (SD) (V1)
LED backlight: 3660L-0374A 201 42 V6 Edge FHD-3 Rev1.0 L-Type / R-Type
T-CON: V6 32/42/47 ARV TM120HZ-TETRA 6870C-0368A
LED driver (backlight): 3PEGC20008A-R PCLF-D002A Rev1.1 6971L-0061A
PWM LED driver: BD9262EF (28)
MOSFET LED driver: AOD482
Power Supply (PSU): DPS-135JP B, 75025645
PWM Power: DDA010 (Standby), DDA014 (18), NCP1608 (PFC)
MOSFET Power: K6A60D, K10A60DR
MainBoard: 32AV833 BTC-202A, 75025658
IC MainBoard: MSD3704PX-LF-SA, H5PS5162FFR, TAS5707L, 25L6445E
Tuner: TDTK-G641D
Control: CT-90326
Specifications 42HL834
TOSHIBA 42HL834R
General repair guidelines for TV LCD LED
Diagnostics of malfunctions and repairs of the TOSHIBA 42HL834R, as well as other electronic devices, is recommended to begin with an external inspection of the external and internal elements. Often, by the external signs and nature of the damage to the elements, it becomes possible to draw some conclusions and determine a further algorithm for finding a defect before making the necessary measurements at control points. If charred resistors, swollen electrolytic or cermet capacitors, ring cracks in the solders of the terminals of transformers or heating elements are found, it is advisable to establish the causes and consequences of the malfunction that has arisen, as well as to check the connected elements and assemblies.
Sometimes the TOSHIBA 42HL834R 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 DPS-135JP B general power module, 75025645. If it is working properly, you need to check the processor batteries on the SSB (Main Board). When repairing the power supply, it is advisable to start the diagnostics by checking the mains fuse and the electrolytic capacitors of the filters of the converter secondary rectifiers. In the event of a fuse breaking, the reason should be sought in the power semiconductor elements of the pulse converter of the main power supply. First of all, it is necessary to check the diodes of the bridge of the rectifier of the mains voltage and the power switch (s) of the converter.
The reasons for the breakdown of the power switch in switching power supplies (IIPS) can be different, for example, a malfunction of semiconductor cells or electrolytic capacitors in the stabilization circuits of the primary circuit, as well as a failure in the operation of the PWM controller chip DDA010 (8), DDA014 (18), NCP1608 (8) or breakage of resistors in its harness.
If the TOSHIBA 42HL834R has no image, there is sound and the channels are switched, there is a possibility of a malfunction in the backlight LED circuit of the LC420EUN (SD) (V1), 75023049 panel, or their power converter - LED drivers. Sometimes when you turn on the image appears and disappears immediately. In such cases, it is necessary to check the electrolytic capacitors of the power filter of the LED driver itself, including in the secondary rectifier of the main PSU.
A malfunction in the backlight circuits often occurs due to an open in the power circuit of the LED lines. It requires disassembling the panel and checking the LEDs themselves, the rations of their terminals, as well as the reliability of the connections in the connectors and rations of the terminals.
It is impossible to check the LED line for breaks without disassembling the panel with a multimeter or tester. For these purposes, it is necessary to open all series-connected PN junctions and a voltage of the order of tens of volts will be required, and ideally, a current source.
In cases of attempts to repair the motherboard 32AV833 BTC-202A, 75025658, it is necessary to check the operability of the stabilizers or power converters of its microcircuits and, if possible, update the software (software). BGA chips can in most cases be diagnosed by local heating.
Complex repair of MB (SSB) is possible only in the conditions of a service center with the necessary equipment. Testing or replacing components MSD3704FX-LF-SA requires the necessary training and professional skills to repair modules at the component level. Problems associated with the use of BGA soldering technologies can be diagnosed by warming up.
Before replacing the TDTK-G641D tuner, if there is no tuning to the channels, you must first check the power supply voltage at its terminals, including the power supply of varicaps (30-33V).
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 Chassis 32AV833/834. Service manual and schematic diagram

 Service Manual 42 pages of 2010 on the models 26EL834G, 26EL834RB, 32EL834B, 32EL834G, 32EL834R, 32HL834G, 32HL834R, 42HL834G, 42HL834R



 The appearance of the MainBoard 32AV833 is shown in the figure below:
32AV833
32AV833 can be used in TVs:
TOSHIBA 26EL833RB (Panel LC260EXN (SD)(A3) 75023140), TOSHIBA 26EL834RB (Panel LC260EXN SD A3), TOSHIBA 32AV833RB (Panel LC320WXN SCC1), TOSHIBA 32EL833G (Panel LC320EXN (SD)(A2)), TOSHIBA 32EL833R 32EL834R (Panel LC320EXN-SDA2 75023687 LCD PANEL), TOSHIBA 32HL833R (Panel LC320EUN SD V1 75022862 LED), TOSHIBA 32HL834R (Panel LC320EUN (SD)(V1)), TOSHIBA 32LV833RB (Panel T315HW04 V4), TOSHIBA 40LV833RB (Panel V400H1-L10), TOSHIBA 42DB833R (Panel LC420EUN (SD)(V1) 75023049), TOSHIBA 42HL833R (Panel LC420EUN (SD)(V1) LED 75023049), TOSHIBA 42HL834R (Panel LC420EUN (SD)(V1)).
PSU Advanced
The 42HL834R TV is equipped with a DPS-135JP 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 NCP1608 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 (of the order of 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
Key Features of the TOSHIBA 42HL834R:
Installed matrix (LED-panel) LC420EUN (SD) (V1).
The matrix control uses the Timing Controller (T-CON) V6.
The LED driver 3PEGC20008A-R is used to power the backlight LEDs, it is controlled by the BD9262EF PWM controller (28). As power elements of the LED driver, keys of the AOD482 type are used.
The necessary supply voltages for all nodes of the TOSHIBA 42HL834R TV are generated by the DPS-135JP power supply module or its analogs using DDA010 (Standby), DDA014 (18), NCP1608 (PFC) microcircuits and power switches of the K6A60D, K10A60DR type.
MainBoard - the main board (motherboard) is a 32AV833 module, using microchips MSD3704PX-LF-SA, H5PS5162FFR, TAS5707L, 25L6445E and others.
The TDTK-G641D tuner provides television reception and channel tuning.
Information from an alternative source:
TOSHIBA 42HL834R
Panel Type (Matrix): LC420EUN,
Motherboard: 32AV833 Rev: 1.0.3, Micom. MSD3704PX-LF-SA, H5PS5162FFR, Audio. TAS5707L, Eeprom. 25L6445E, Tuner: TDTK-G641D 04A9-00A4000,
T-con: 94V0G, TL2344ML, TPS65168, TPS65194, BUF08630, 456RK, Led driver: 3PEGC20008A-R, BD9262EFV, AOD482,
PSU: PE-3900-01UN-LF, FAN7930, STR-A6069H, FSFR180
Remote control: CT-90326
Additional technical information about the panel:
Brand: LG Display
Model: LC420EUN-SDV1
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 930.24x523.26 mm
Surface: Antiglare (Haze 10%), Hard coating (3H)
Brightness: 360 cd / m²
Contrast Ratio: 1400: 1
Display Colors: 16.7M (8-bit), CIE1931 68%
Response Time: 6 (G to G)
Frequency: 60Hz
Lamp Type: WLED Embedded (LED Driver)
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V

 Brand: TOSHIBA, Model: 42HL834.
Shortly from the TV: LCD, LED backlight, 42 ", 1920x1080, 1080p Full HD, sound: 14W, HDMI connectors: 2.
For the 42HL834G model, the official website has firmware (software update) version 1.05.
The composition includes MainBoard 32AV833 BTC-202A 75025658 and LCD panel (matrix) LC420EUN (SD) (V1).
Power Supply Unit (PSU) DPS-135JP B 75025645 Power Supply.

TOSHIBA 42HL834 LED TV with LC420EUN LCD display, 42 "(107 cm) diagonal size in 16: 9 format. The required screen brightness of 360 cd / m² is provided by LED backlighting. The ratio of maximum brightness to minimum (contrast) is 1400: 1 Dynamic contrast ratio of 3,000,000: 1 is achieved by special control of the LEDs. This model uses side LED backlighting 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 it is in a graphic decomposition according to the standard 1080p (Full HD). The input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p Supported media file formats: MP3, MPEG4, Xvid, MKV, JPEG.
The power of the speaker system of sound 14 W (2x7 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, audio x2, component, SCART, RGB, VGA, HDMI x2, 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, 1024x768, 1280x1024, 1360x768.
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 81 watts.
Overall dimensions: with stand 1070x677x238 mm, without stand 1070x630x45 mm.
TV Weight: with stand: 15 kg, without stand: 13.6 kg.
Attention! The LC420EUN (SD) (V1) panel of the TOSHIBA 42HL834 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.