Tuesday, 31 March 2020

REPAIR / SERVICING TV TOSHIBA 42AV500PSR

Technical description and composition of the TOSHIBA 42AV500PSR TV, type of panel and applicable modules. The composition of the modules.
Toshiba
Model: 42AV500PSR
Panel: LC420WXN (SA) (B1) // LC420WX7-SLC1
T-CON: 75013100 // 75009703
Inverter (backlight): 75013089 // 75009702
Power Supply (PSU): PE0643 A U03A MAIN_POWER
PWM Power: STR-Y6476, STR-Z2467
MainBoard: PE0484 U01AS
IC MainBoard: TDA8891H1 / N1B TDA15451HV / N1B00
Tuner: TAEA-G081D
Control: CT-90298
Specifications 42AV500PR
TOSHIBA 42AV500PSR
General recommendations for repairing TV LCD
Repair of the TOSHIBA 42AV500PSR TV is best started with a thorough external inspection and diagnosis of the malfunction. It is advisable to carefully examine the internal and external components. Sometimes, only by some signs can we determine the further direction of the localization of the fault. Elements with visible damage, for example, capacitors swelled up after boiling the electrolyte, charred resistors in certain nodes of the circuit, as well as ring cracks in solders will help the master to guess the causes and possible consequences of the malfunction.
Faults in the U03A MAIN_POWER power module (PE0643A) can be expressed in different ways, for example, the TOSHIBA 42AV500PSR does not turn on at all and the control lamps on its front panel do not light up and do not blink, and there are no signs of operability. The diagnostics of the power supply should always be started by checking the fuse and, if it is broken, it is first necessary to check the rectifier bridge diodes and the power switch for the likelihood of an avalanche or thermal breakdown.
It should be remembered that the N-FET keys used in flyback converters rarely fail for no reason that must be sought by checking other elements of the circuit. Often the breakdown is caused by malfunctions of electrolytic capacitors or semiconductor elements in the primary circuit, or by a break in the resistors in the stabilization circuits. The PWM controller chip STRY6476 STR-Z2467 can also cause a breakdown of the power switch of the converter.
When using the Active Power Factor Correction (CMC) circuitry in the power module, the search for faulty elements is somewhat more complicated.
If there is no image when you turn on the TOSHIBA 42AV500PSR, or it appears for a second and disappears completely, but there is sound, most likely either the backlight lamps or their power converter (inverter) are faulty. It is necessary to check the electrolytic capacitors of the filter of the secondary rectifiers in the general power supply unit.
Repair of the inverter 75013089 // 75009702 is complicated by the fact that in case of any malfunction or emergency, even with uneven wear of the lamps, a protection is triggered, which turns it off for fire safety. Diagnostics become impossible and protection needs to be disabled.
All necessary precautions must be observed when disabling the inverter protection during diagnostics and not leaving it disconnected after the repair is completed.
On the motherboard U01AS SIGNAL (PE0484), in the event of a malfunction, you should first check the operation of all the power stabilizers of the microcircuits and, if necessary, update the software (software). In cases of attempts to repair the MB board (SSB), it is necessary to check the health of its elements - TDA8891H1 / N1B TDA15451HV / N1B00 which may require replacement with new ones.
Before changing the tuner TAEA-G081D, if it is not possible to tune to television channels, make sure that there are supply voltages, including varicap power (30-33V), which must be measured on the corresponding tuner pins.
For owners of the 42AV500PSR TV, we recommend that you contact qualified professionals with experience to repair! Self-repair attempts without the appropriate knowledge and skills can lead to serious negative consequences!

SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    37/42AV500Ps PE0484 PE0486 PE0643


 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).
Key Features of the TOSHIBA 42AV500PSR:
Installed matrix (LCD panel) LC420WXN (SA) (B1) or LC420WX7-SLC1.
The matrix control uses the Timing Controller (T-CON) 75013100.
An inverter 75013089 is used to power the backlight.
The necessary supply voltages for all nodes of the TOSHIBA 42AV500PSR TV are generated by the PE0643 power module or its analogs using the STR-Y6476, STR-Z2467 microcircuits.
MainBoard - the main board (motherboard) is a PE0484 module, using TDA8891H1 / N1B TDA15451HV / N1B00 chips and others.
The TAEA-G081D tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: LG.Philips LCD
Model: LC420WXN-SAB1
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1366x768, WXGA
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 930.25x523.01 mm
Surface: Antiglare (Haze 13%), Hard coating (3H)
Brightness: 500 cd / m²
Contrast Ratio: 1100: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 5 (G to G)
Frequency: 60Hz
Lamp Type: EEFL Embedded (Inverter)
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V

 TOSHIBA 42AV500PR LCD TV with 42 "(106 cm) diagonal LCD display, 16: 9 format. The ratio of maximum brightness to minimum (contrast) is 1100: 1. Dynamic contrast ratio of 17000: 1 is achieved by special control of the backlight. Viewing is possible images in high quality HD at a resolution of 1366x768 pixels in the standard for 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 in the standard 480i, 480p, 576i, 576p, 720p, 1080i.
The power of the acoustic system of sound 20 W (2x10 W) provide 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 x3, component, SCART x2, RGB, 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.
The power consumed by the TV in the operating mode from the network is 215 watts.
Overall dimensions: with stand 1006x675x264 mm, without stand 1006x635x102 mm.
TV mass: with stand: 19.6 kg, without stand: 18.2 kg.
Attention! The TOSHIBA 42AV500PR LCD TV panel is its most expensive component.
Avoid hitting the glass and exerting pressure on the screen to avoid permanent damage to the LCD panel!