Thursday, 26 March 2020

REPAIR / SERVICING TV TOSHIBA 26AV603PR

Technical description and composition of the TOSHIBA 26AV603PR TV, type of panel and applicable modules. The composition of the modules.
Toshiba
Model: 26AV603PR
Panel: LTA260AP02 75014399
T-CON: 75015790
Inverter (backlight): 75015804
MainBoard: 715G3431 / 715G3385
IC MainBoard: CPU: MST9A885GL
Tuner: TAFT-S710D
Specifications 26AV603P
TOSHIBA 26AV603PR
General recommendations for repairing TV LCD
TOSHIBA 26AV603PR TV, like any other, it is advisable to start repairing it by inspecting the internal and external visible physical visual changes. In some cases, visible external damage to the elements can suggest directions for troubleshooting and localizing the defect before starting the necessary measurements at the control points of the nodes of electronic circuits. In most cases, the repairman can guess the causes of the defect and possible consequences by the characteristic signs of typical TV defects, for example, ring cracks formed in the soldering of element leads, swollen rectifier filter capacitors, charred resistors and other circuit elements.
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 probability that the power 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. When diagnosing and repairing the power supply, first of all, it is necessary to check the fuse and, if it is broken, it is necessary to identify the cause. Often in such cases, an avalanche (thermal) breakdown is detected in the power semiconductor elements of the module - rectifier diodes or power key.
Power switches in flyback converters fail extremely rarely for no reason and, if they are broken, it is necessary to look for a malfunction in the stabilization circuits by checking electrolytic capacitors, semiconductor devices, and resistors in the primary circuit. The cause may be a malfunction of the PWM controller chip, which can only be checked by replacing it with a new or obviously working one.
When using a power factor correction unit (PFC) in the power modules, troubleshooting becomes somewhat more complicated and requires additional experience and knowledge of their operation.
If the TOSHIBA 26AV603PR has no image, but there is sound and the TV is controlled by the remote control, a malfunction in the display backlight nodes is likely. The lamps or the power converter - inverter may be faulty. Often in such cases, when you turn on the TV, an image appears and immediately disappears. First of all, it is necessary to verify the operability of the electrolytic capacitors of the rectifier filter supplying the inverter, and check the LCD lamps by connecting external and obviously serviceable for diagnosis to the connectors.
Repair of the inverter 75015804 can often be somewhat complicated by the use of special protection circuits, which are designed to disconnect it in emergency cases for fire safety when the lamps are depressurized, or short circuits or breaks in high-voltage circuits and connections. Sometimes it becomes necessary for diagnostic purposes to block the protection circuits in order to be able to make the necessary measurements at the control points of the circuit.
All necessary precautions must be observed when disabling the inverter protection during diagnostics and not leaving it disconnected after the repair is completed.
Owners of the 26AV603PR TV are recommended for repairs to contact only qualified specialists with experience! Self-repair attempts without the appropriate knowledge and skills can lead to serious negative consequences!


SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    Toshiba 26/32AV603P


 Service Manual 70 pages on the model 26AV603PG, 32AV603PG, 32AV605PB, 32AV607PG, 32AV615DB

 The appearance of the MainBoard 715G3431 is shown in the figure below:
715G3431
715G3431 can be used in TVs:
TOSHIBA 26AV603PR (Panel LTA260AP02 75014399), TOSHIBA 32AV603PR (Panel LC320WXN (SB)(B1) 75013857), TOSHIBA 32AV607PR (Panel LC320WXN-SBB1 (75013857)), TOSHIBA 32AV615DG (Panel LC320WXN (SB)(B1)).
Main features of the TOSHIBA 26AV603PR device:
Installed matrix (LCD panel) LTA260AP02 75014399.
The matrix control uses the Timing Controller (T-CON) 75015790.
An inverter 75015804 is used to power the backlight.
The required supply voltage for all nodes of the TOSHIBA 26AV603PR TV is provided by a switching power supply.
MainBoard - the main board (motherboard) is a 715G3431 module using CPU chips: MST9A885GL and others.
The TAFT-S710D tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: SAMSUNG
Model: LTA260AP02
Type: a-Si TFT-LCD, Panel
Diagonal size: 26.0 inch
Resolution: 1366x768, WXGA
Display Mode: APVA, Normally Black, Transmissive
Active Area: 575.769x323.712 mm
Surface: Antiglare (Haze 14%), Hard coating (3H)
Brightness: 450 cd / m²
Contrast Ratio: 4000: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 8 (G to G)
Frequency: 60Hz
Lamp Type: 4 pcs CCFL Embedded (Inverter)
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V

 TOSHIBA 26AV603P LCD TV with an LTA260AP02 LCD display, 26 "(66 cm) diagonal size in 16: 9 format. The ratio of maximum brightness to minimum (contrast) is 5000: 1. Dynamic contrast ratio of 50,000: 1 is achieved by special control of the backlight. Possible viewing images in high quality HD at a resolution of 1366x768 pixels in the standard of graphic 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 takes place in standard artworks 480i, 480p, 576i, 576p, 720p, 1080i.
The power of the sound system 10 W (2x5 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 x3, component, SCART x2, RGB, VGA, HDMI x3. 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 120 watts.
Overall dimensions: with stand 667x494x240 mm, without stand 667x448x90 mm.
TV Weight: with stand: 10.5 kg, without stand: 9.4 kg.
Attention! The TOSHIBA 26AV603P LCD TV panel LTA260AP02 is its most expensive component.
Avoid hitting the glass and exerting pressure on the screen to avoid permanent damage to the LCD panel!