Thursday 26 March 2020

REPAIR / SERVICING TV TOSHIBA 24PB1

Technical description and composition of the TOSHIBA 24PB1 TV, type of panel and applicable modules. The composition of the modules.
TOSHIBA 3 LAMP CCFL
Model: 24PB1 24PB1E
Chassis / Version: PE0942
Panel: T240XW01 V.1 XXXXG
T-CON: 240XW01 V.1 CTRL BD; AUO-11303
Inverter (backlight): integrated into PSU
PWM Inverter: BD9893F
MOSFET Inverter: 5N52U
Power Supply (PSU): PSIV750401A V71A00021600
PWM Power: SEM3040, STR-W6052S
MOSFET Power: 10NM60 (PFC)
MainBoard: PE0942 V28A001240A1
IC MainBoard: CPU: MST9B884JL-LF-3, SPI FLASH: W9412G6JH, EEPROM: 24C08K, Audio: TAS5708
Tuner: TDTK-G732D V86A00014800
Specifications 24PB1
TOSHIBA 24PB1
General repair instructions for TV LCD 3 LAMP CCFL
Possible malfunctions
- TOSHIBA 24PB1 does not turn on, the indicators on the front panel do not light or flash. The TV does not respond to the control buttons and the remote control.
With such manifestations, the PSIV750401A power module usually fails. It is necessary to measure its output voltages and, if they are absent, to check for short-circuit probability in the converters, power switches (10NM60 (PFC)) and rectifier diodes.
In case of any breakdowns in the secondary circuits, the converter can operate in emergency short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse or the current sensor at the source of the key more often breaks.
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 circuits (OOS) of stabilization. PWM controllers (PWM) SEM3040, STR-W6052S, if they do not have visible damage to the case and open short circuit between the terminals, are usually checked by replacement.
- There is no image, but there is sound and reaction to commands from the remote control. Or the image appears immediately after turning on and disappears.
The defect can be caused by problems in the nodes or elements of the backlight of the display, or in the power supply of the lamps or inverter. If all the electrolytic capacitors of the filter according to the power supply of the inverter are working, make sure that the lamps are working, then you need to check the converter keys and the secondary windings of the transformers.
If in diagnosing a malfunction, it is necessary to disable the inverter protection, there is a risk of failure of the power elements of the inverter, and special care is required during work, and after they are finished, it is necessary to restore the protection circuits for further safe operation of the TV by the owner in normal mode.
- 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 PE0942 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). Sometimes it is necessary to check or replace (if necessary) the elements of the MainBoard - CPU: MST9B884JL-LF-3, SPI FLASH: W9412G6JH, Audio: TAS5708. In cases where the BGA processor is used, its malfunction is usually detected by the local heating method.
Before replacing the TDTK-G732D V86A00014800 tuner, if there is no tuning for the channels, you must first check the software and the supply voltage at its terminals. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus
Once again, remind users! Attempts to independently repair the TOSHIBA 24PB1 TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!


Repair MainBoard
The appearance of MainBoard PE0942 is shown in the figure below:
PE0942
Main features of the TOSHIBA 24PB1 device:
Installed matrix (3 LAMP CCFL panel) T240XW01 V.1 XXXXG.
The matrix control uses the Timing Controller (T-CON) 240XW01.
To power the backlight LEDs, a converter is used, combined with the power supply, controlled by the BD9893F PWM controller. As power elements of the inverter, keys of the 5N52U type are used.
The necessary supply voltages for all nodes of the TOSHIBA 24PB1 TV are generated by the PSIV750401A power supply module or its analogs using SEM3040, STR-W6052S microcircuits and 10NM60 type power switches (PFC).
MainBoard - the main board (motherboard) is a PE0942 module using CPU chips: MST9B884JL-LF-3, SPI FLASH: W9412G6JH, EEPROM: 24C08K, Audio: TAS5708 and others.
Tuner TDTK-G732D V86A00014800 provides the reception of television programs and tuning to channels.



Brand: TOSHIBA, Model: 24PB1.
Short from TV: LCD, 24 ", 1366x768, 720p HD, sound: 20 watts.
The composition includes MainBoard PE0942 V28A001240A1 and an LCD panel (matrix) T240XW01 V.1 XXXXG.
Power Supply Unit (PSU) PSIV750401A V71A00021600 Power Supply.
TOSHIBA 24PB1 LCD TV with T240XW01 LCD, 24 "(61 cm) diagonal size in 16: 9 format. Dynamic contrast ratio of 20,000: 1 is achieved by special backlight control. You can view images in high quality HD at a resolution of 1366x768 pixels in graphic standard decomposition 720p (HD Ready). The input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats : JPEG.
The power of the sound system 20 W (2x10 W) provides two speakers. The audio processing system NICAM STEREO is used.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, audio x2, component, VGA, HDMI, 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.
The power consumed by the TV in the operating mode from the network is 65 watts.
Overall dimensions: with stand 684x483x195 mm, without stand 684x437x87 mm.
TV mass: with stand: 5.5 kg, without stand: 5.1 kg.
Attention! The T240XW01 V.1 XXXXG panel of the TOSHIBA 24PB1 LCD TV is its most expensive component.
Avoid hitting the glass and exerting pressure on the screen to avoid permanent damage to the LCD panel!