Friday 27 March 2020

REPAIR / SERVICING TV TOSHIBA 32AV502PR

Technical description and composition of the TOSHIBA 32AV502PR TV, type of panel and applicable modules. The composition of the modules.
Toshiba
Model: 32AV502PR
Panel: LK315T3LA31 (75012574)
Inverter (backlight): 75014093
Mainboard: PE0484
IC MainBoard: TDA8891 TDA15451 LPC924F TL2417;
Tuner: TAEA-G081D
Specifications 32AV502PR
TOSHIBA 32AV502PR
General recommendations for repairing TV LCD
TOSHIBA 32AV502PR TV, like any other, it is advisable to start repairing it by inspecting the internal and external visible physical visual changes. Any external damage can sometimes prompt the repairman to take further steps to determine the malfunction of the TV and localize the defect. Ring cracks in the soldering of the leads of the heating elements, swollen electrolytic capacitors, a charred paint layer on the resistors - all this for the repairman can be a hint in the assumptions about the causes and consequences of the malfunction.
If the TOSHIBA 32AV502PR does not turn on, no control lights on the front panel light up or blink, therefore, there is a very high probability of a power module malfunction. When repairing the power supply, it is advisable to start the diagnostics by checking the mains fuse and, in the event of an open circuit, the reason should be sought in the power semiconductor elements of the pulsed flyback converter of the main PSU. First of all, it is necessary to check the diodes of the bridge of the rectifier of the mains voltage and the power switch of the converter, which can be installed separately on the radiator, or integrated with a PWM controller.
It should be remembered that in the practice of repair, usually the power keys of N-Fet converters 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 PWM controller chip itself may be faulty. It is also necessary to check all the semiconductor elements of the stabilization circuit in the primary and secondary circuits.
If the power module uses an active KKM circuit (power factor control), troubleshooting is somewhat more complicated.
If the TOSHIBA 32AV502PR does not have an image, there is sound and the channels are switched, there is a possibility of a malfunction of the display backlight, or their power converter - inverter. 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 inverter itself, including in the secondary rectifier of the main PSU.
The operation of the power circuits of the inverter and the backlight in the normal mode are controlled by special protection, which is organized for fire safety, for example, to disconnect during short circuits or breaks in high-voltage connections or when the lamps are depressurized. This protection makes it difficult to diagnose and repair the inverter.
In these cases, special care must be taken in view of the risk of failure of the power elements. After completing all repair work, it is imperative to restore the protection circuits for full and safe further operation of the TV by the user.
Attention to the owners! Attempts to self-repair the TOSHIBA 32AV502PR TV are not recommended by the manufacturer and can lead to serious negative consequences!


SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    Toshiba 32AV502PR. Service manual and schematic diagram

 The appearance of MainBoard PE0484 is shown in the figure below:
PE0484
PE0484 can be used in TVs:
TOSHIBA 32AV500PR (Panel LC320WXN (SB)(B1)), TOSHIBA 32AV500PSR (Panel LC320WXN (SB)(B1)), TOSHIBA 32AV501PR (Panel LK315T3LA31), TOSHIBA 32AV502PR (Panel LK315T3LA31 (75012574)), TOSHIBA 37AV502PR (Panel LC370WXN(SA)(C2) 75012583), TOSHIBA 42AV500PSR (Panel LC420WXN (SA)(B1)), TOSHIBA 42AV501PR (Panel LC420WX7-SLC1), TOSHIBA 42AV502PR (Panel LC420WXN-SAB1), TOSHIBA 37AV500PR (Panel AX094B002B).
Main features of the TOSHIBA 32AV502PR device:
Installed matrix (LCD panel) LK315T3LA31 (75012574).
An inverter 75014093 is used to power the backlight.
The required supply voltage for all nodes of the TOSHIBA 32AV502PR TV provides a switching power supply.
MainBoard - the main board (motherboard) is a PE0484 module, using TDA8891 TDA15451 LPC924F TL2417 chips; and others.
The TAEA-G081D tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: SHARP
Model: LK315T3LA31
Type: a-Si TFT-LCD, Panel
Diagonal size: 31.5 inch
Resolution: 1366x768, WXGA
Display Mode: ASV, Normally Black, Transmissive
Active Area: 697.68x392.26 mm
Surface: Antiglare, Hard coating (3H)
Brightness: 450 cd / m²
Contrast Ratio: 2000: 1
Display Colors: 16.7M (8-bit)
Response Time: 7 (G to G)
Frequency: 60Hz
Lamp Type: 10 pcs CCFL Embedded (Inverter)
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V

 TOSHIBA 32AV502PR LCD TV with LK315T3LA31 LCD display, 32 "(81 cm) diagonal size in 16: 9 format. 800 cd / m² screen brightness is provided by CCFL (EEFL) fluorescent lamps. Dynamic contrast ratio of 20,000: 1 is achieved by special operation control It is possible to view 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 occurs It in the standards 480i, 480p, 576i, 576p, 720p, 1080i.
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 x2, audio x5, S-Video, component x2, SCART x2, RGB, VGA, HDMI x2. 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, 1360x768.
The power consumed by the TV in the operating mode from the network is 137 watts.
Overall dimensions: with stand 796x552x224 mm, without stand 796x512x99 mm.
TV Weight: with stand: 12.9 kg, without stand: 12.1 kg.
Attention! The LK315T3LA31 75012574 panel of the TOSHIBA 32AV502PR 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!