Saturday, 6 February 2021

REPAIRING / SERVICING TV TOSHIBA 32L5865

Technical description and composition of the TOSHIBA 32L5865 TV, panel type and modules used. The composition of the modules.

TOSHIBA LED
Model: 32L5865 32L5865EV

Chassis / Version: RSAG7.820.7924

Panel: JHD315S1H71

LED backlight: CRH-BT32S1303006027ADREV1.2

LED driver (backlight): integrated into MainBoard

PWM LED driver: HOZ1GN (AP3843C)

MOSFET LED driver: CS630A4H

Power Supply (PSU): integrated into MainBoard

PWM Power: OZ531TGN

MOSFET Power: AOB7S65L

MainBoard: RSAG7.820.7924 / ROH

IC MainBoard: CPU: MT5659DUHT, eMMC: THGBMBG5D1KBAIL

Tuner: SCTS2-85 / 116H-FJ4 / ROH

Control: IR: RSAG7.820.7934, WiFi: ZDWFM2402 M2652_V1.00

Specifications 32L5865EV
TOSHIBA 32L5865
General recommendations for TV LCD LED repair
Possible manifestations of defects

- TOSHIBA 32L5865 does not turn on, indicators on the front panel do not light or flash. The TV does not respond to the control buttons and the remote control.

In such cases, the main power source may be faulty - the AC / DC converter of the mains voltage, which is combined with the MainBoard RSAG7.820.7924. It is then necessary to measure its output voltages and, if they are absent, the power switches (AOB7S65L) and rectifier diodes of the converters should be checked for the probability of a short circuit.
In case of breakdowns of semiconductors in the secondary circuits, the converter can usually operate in an emergency in the short-circuit mode, and in the event of a short circuit in the power elements of the primary circuit, the mains fuse often breaks.
Breakdown of Mos-Fet switches used in switching power supplies is often caused by malfunctions of other elements, for example, in the power supply circuit of a PWM regulator, in frequency-setting or damper circuits, as well as in negative feedback stabilization. PWM microcircuits (PWM) OZ531TGN are usually checked by replacing them with new ones, or knowingly working.

- There is no picture, but there is sound and all other functions work. Sometimes when you turn it on, the image appears and disappears for a second.

As a rule, in this case, the backlight of the LED panel is faulty. The reason can sometimes be in the power supply of the LEDs, but more often in their malfunction (breakdown or open circuit), sometimes in the violation of the contact connections of the CRH-BT32S1303006027ADREV1.2 LED strips.
When trying to detect a break in the LED lines, it should be borne in mind that it is difficult to do this without disassembling the panel. For example, a current source is needed to open PN junctions connected in series.

In cases where TOSHIBA 32L5865EV has no picture, but there is sound, the display backlight often does not work.
In LED TVs, the LEDs inside the JHD315S1H71 panel are usually faulty, and less often the LED driver.
Without backlighting, sometimes you can see a barely noticeable image with a certain successful hit of external light on the screen.

Replacing the LEDs requires disassembling the JHD315S1H71 panel. We do not recommend such works on their own to TV owners and craftsmen who do not have experience in repairing LCD panels, especially at home.

If there is no image, and the backlight is on, the screen becomes slightly lighter when turned on, and on an open TV, the light is visible through the holes in the panel case.
In this case, the T-CON (Timing Controller) board may be defective, but often the MainBoard RSAG7.820.7924 is also defective. A software failure is also possible. The panel may also be faulty - damage to strips, loops, for example, after moisture ingress. In such cases, first of all, it is necessary to check the panel supply voltage at the LVDS connector, the fuses on the T-CON board or the panel brackets, as well as the supply and reference voltages for column and line drivers - VGH, VGL, Vcom.
If they are within the normal range, then the oscilloscope needs to track the passage of LVDS signals from MainBoard RSAG7.820.7924, as well as synchronizing signals to loops with drivers.

Flooded screens of LED TVs can sometimes be repaired if no significant damage has formed in the loops and on the panel trims.


- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals the standby mode.

Repair or diagnostics of the RSAG7.820.7924 motherboard should begin with checking the stabilizers and power converters necessary to power the microcircuits and matrix. If necessary, you should update or replace the software (software). In some cases, to repair the MB (SSB) board, it may be necessary to replace the chips - CPU: MT5659DUHT, eMMC: THGBMBG5D1KBAIL with new or known good ones. In cases where BGA technologies are used, defects are usually localized by heating.

If you suspect a malfunction of the SCTS2-85 / 116H-FJ4 / ROH tuner, first of all, you need to make sure that the software is correct, as well as the presence of the required supply voltage levels and pulses of data exchange with the processor via the I2C bus on the corresponding tuner pins.

Owners of the 32L5865 TV are advised to contact only qualified specialists with the necessary experience for repair! Attempts to repair yourself without the appropriate knowledge and skills can lead to irreversible negative consequences!


DOWNLOAD SCHEMATIC DIAGRAM  / POWER SUPPLY   ------------------>   RSAG7.820.7924 Power supply



The appearance of the MainBoard RSAG7.820.7924 is shown in the figure below:



RSAG7.820.7924

The main features of the TOSHIBA 32L5865 device:

Installed matrix (LED panel) JHD315S1H71.
To power the backlight LEDs, a converter combined with the RSAG7.820.7924 main board is used, controlled by the HOZ1GN PWM controller (AP3843C). The keys of the CS630A4H type are used as power elements of the LED driver.
The power module is combined with the MainBoard and is made according to the AC / DC flyback voltage converter circuit using OZ531TGN microcircuits and AOB7S65L power switches.
MainBoard - the main board (motherboard) is a RSAG7.820.7924 module, using CPU chips: MT5659DUHT, eMMC: THGBMBG5D1KBAIL and others.
The SCTS2-85 / 116H-FJ4 / ROH tuner provides reception of television programs and tuning to channels.


LED TV TOSHIBA 32L5865EV with LCD display, diagonal size 32 "(81 cm) 16: 9. The required brightness of the screen 275 cd / m2 is provided by LED backlighting. The ratio of maximum brightness to minimum (contrast) is 1200: 1. The LCD panel uses Direct LED backlighting.
The design and capabilities of the TV realize HD picture quality at a resolution of 1366x768 pixels in 720p (HD Ready).
The 32L5865EV TV is equipped with SMART software, built-in applications and the ability to work on the Internet. Internet connection can be made via Wi-Fi wireless connection. Supported media file formats: MP3, WMA, MPEG4, HEVC (H.265), DivX, MKV, JPEG.
Speaker power 16 W (2x8 W) is provided by two speakers. Uses the NICAM stereo signal processing system and the Sound Surround function.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, HDMI x2, USB x2, Ethernet (RJ-45), Wi-Fi. A headphone output is provided. The digital tuner is capable of receiving television channels in the DVB-T, DVB-T2, DVB-C, DVB-S, DVB-S2 standards.

Dimensions: with stand 734x465x171 mm, without stand 734x440x76 mm.

TV weight: with stand: 4.4 kg, without stand: 4.3 kg.

Attention! The panel of the TOSHIBA 32L5865EV LED TV is an expensive and unreliable element.
Do not allow any impact on the glass and pressure on the screen surface to avoid damage to the LED panel!


It is also unsafe for liquid to spill onto the screen. Sometimes one drop is enough if it drips down the glass onto the cables to make the TV unrepairable.