Tuesday, 31 March 2020

REPAIR / SERVICING TV TOSHIBA 40LV655PR

Technical description and composition of the TOSHIBA 40LV655PR TV, type of panel and applicable modules. The composition of the modules.
Toshiba
Model: 40LV655PR
Panel: LTA400HA11
T-CON: SYNC60C4LV0.3
Inverter (backlight): SSI_400_14A01 INV40N14A
PWM Inverter: SEM2107
MOSFET Inverter: AO4614
Power Supply (PSU): DPS-276AP A
PWM Power: A6069H (Standby 7pin), NCP1607B, DAP015D
MOSFET Power: 15N60C, K10A60D
MainBoard: PE0772 V28A001020A1
IC MainBoard: Cpu: MST 6B885GL-LF-3, Flash: 26DF161A, Eeprom: 24C08W, Audio: TAS6705
Tuner: TAEA-G059D
Specifications 40LV655P
TOSHIBA 40LV655PR
General recommendations for repairing TV LCD
Possible manifestations of defects
- The TOSHIBA 40LV655PR TV does not turn on, does not respond to the remote control and the control panel buttons, the indicators do not light or flash.
With such manifestations, in most cases the DPS-276AP power supply module is faulty. It is then necessary to measure its output voltages and, if they are absent, you should check the power switches (15N60C, K10A60D) and the rectifier diodes of the converters for a short circuit probability.
During thermal or avalanche breakdowns of semiconductors in the secondary circuits of any converter, as a rule, it can operate in emergency short circuit mode without output voltages, and during short circuit in the elements of the primary circuit, the main fuse and, less often, the current sensor at the source of the key are most often cut off.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke an excess of the maximum current or voltage. It can be supply, damper circuits, or elements of OOS (negative feedback) stabilization. The reason for the breakdown of the power switch may be PWM (PWM) A6069H (Standby 7pin), NCP1607B, DAP015D. It is checked only by replacement with a known good one.
- 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.
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.
Sometimes, for diagnostic purposes, it is necessary to disable the inverter protection. In such cases, special care must be taken during work, and the protection circuits should be restored immediately after the repair is completed.
- The TV does not enter the operating mode, does not respond to the remote control. The indicator on the front panel lights constantly or blinks.
Repair or diagnostics of the PE0772 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 they require checking or replacing (if necessary) the elements of the MainBoard board - Cpu: MST 6B885GL-LF-3, Flash: 26DF161A, Eeprom: 24C08W, Audio: TAS6705. In cases where the BGA processor is used, its malfunction is usually detected by the local heating method.
The malfunction of the TAEA-G059D tuner is established after checking the software and all supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be controlled by an oscilloscope.
We recommend the owners of the 40LV655PR TV for repair only to qualified specialists with the necessary work experience! Self-repair attempts without the appropriate knowledge and skills can lead to irreversible negative consequences!



Repair MainBoard
The appearance of MainBoard PE0772 is shown in the figure below:
PE0772
PE0772 can be used in TVs:
TOSHIBA 32AV655PR (Panel LK315T3LA51), TOSHIBA 40LV655PR (Panel LTA400HA11).
The appearance of the power supply
Main features of the TOSHIBA 40LV655PR device:
Installed matrix (LCD-panel) LTA400HA11.
The matrix control uses the Timing Controller (T-CON) SYNC60C4LV0.3.
To power the backlight, an SSI_400_14A01 inverter is used, it is controlled by the PWM controller SEM2107. As power elements of the inverter, keys of the type AO4614 are used.
The necessary supply voltages for all nodes of the TOSHIBA 40LV655PR TV are generated by the DPS-276AP power module or its analogs using A6069H (Standby 7pin), NCP1607B, DAP015D microcircuits and power switches of the 15N60C, K10A60D type.
MainBoard - the main board (motherboard) is a PE0772 module, using Cpu: MST 6B885GL-LF-3, Flash: 26DF161A, Eeprom: 24C08W, Audio: TAS6705 and others.
The TAEA-G059D tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: SAMSUNG
Model: LTA400HA11
Type: a-Si TFT-LCD, Panel
Diagonal size: 40 inch
Resolution: 1920x1080, FHD
Display Mode: S-PVA, Normally Black, Transmissive
Active Area: 885.6x498.15 mm
Surface: Antiglare (Haze 14%), Hard coating (3H)
Brightness: 500 cd / m²
Contrast Ratio: 3000: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 8 (G to G)
Frequency: 60Hz
Lamp Type: 16 pcs CCFL Embedded (Inverter)
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V

Short from TV: LCD, 40 ", 1920x1080, 1080p Full HD, sound: 20W, HDMI: 3.
For the 40LV655P model, the official website has firmware (software update) version 2.1.77.2.
The composition uses MainBoard PE0772 V28A001020A1 and an LCD panel (matrix) LTA400HA11.
Power Supply Unit (PSU) DPS-276AP A Power Supply.
TOSHIBA 40LV655P LCD TV with 40 "(102 cm) diagonal LCD display in 16: 9 format. Screen brightness of 500 cd / m² is provided by CCFL (EEFL) fluorescent lamps. Dynamic contrast ratio of 50,000: 1 is achieved by special control of operation The design and technical capabilities of the TV include viewing programs and movies in high quality HD with a resolution of 1920x1080 pixels in graphic resolution 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: JPEG.
The power of the sound acoustic system is 20 W (2x10 W). 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 x3, S-Video, component, SCART x2, RGB, VGA, HDMI x3, 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, 1920x1080.
The power consumed by the TV in the operating mode from the network is 183 watts.
Overall dimensions: with stand 976x663x351 mm, without stand 976x623x92 mm.
TV Weight: with stand: 19 kg, without stand: 17.4 kg.
Attention! The TOSHIBA 40LV655P LCD TV panel LTA400HA11 is its most expensive component.
Avoid hitting the glass and exerting pressure on the screen to avoid permanent damage to the LCD panel!