REPAIRING AND NOT THROWING AWAY

REPAIRING AND NOT THROWING AWAY

Richtige Fernseher haben Röhren!

Richtige Fernseher haben Röhren!

In Brief: On this site you will find pictures and technical information about Service Modes, Circuit Diagrams, Firmware Update procedure, Disassemble procedure, Universal remote control set-up codes, Troubleshooting and more....

If you go into the profession, you will obtain or have access to a variety of tech tips databases HERE IT IS Master Electronics Repair !.

These are an excellent investment where the saying: 'time-is-money' rules. However, to learn, you need to develop a general troubleshooting approach - a logical, methodical, method of narrowing down the problem. A tech tip database might suggest: 'Replace C536' for a particular symptom. This is good advice for a specific problem on one model. However, what you really want to understand is why C536 was the cause and how to pinpoint the culprit in general even if you don't have a service manual or schematic and your tech tip database doesn't have an entry for your sick TV or VCR.

While schematics are nice, you won't always have them or be able to justify the purchase for a one-of repair. Therefore, in many cases, some reverse engineering will be necessary. The time will be well spent since even if you don't see another instance of the same model in your entire lifetime, you will have learned something in the process that can be applied to other equipment problems.
As always, when you get stuck, checking out a tech-tips database may quickly identify your problem and solution.In that case, you can greatly simplify your troubleshooting or at least confirm a diagnosis before ordering parts.

Happy repairing!
Today, the West is headed for the abyss. For the ultimate fate of our disposable society is for that society itself to be disposed of. And this will happen sooner, rather than later.

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..............The bitterness of poor quality is remembered long after the sweetness of todays funny gadgets low price has faded from memory........ . . . . . .....
Don't forget the past, the end of the world is upon us! Pretty soon it will all turn to dust!

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Monday 31 August 2020

REPAIRING / SERVICING TV GOLDSTAR LT-50T450F

Technical description and composition of the GOLDSTAR LT-50T450F TV, panel type and modules used. The composition of the modules.
GOLDSTAR LED
Model: LT-50T450F
Chassis / Version: V1R04
Panel: LC490DUJ-SHA2
LED backlight: 5800-W49001-1P00 VER02.00
LED driver (backlight): integrated into PSU
PWM LED driver: OZ9903GN
Power Supply (PSU): 168P-L5L017-W3 5800-L5L017-W300
PWM Power: TEA1733
MainBoard: 5800-A6M33G-0P20 VER00.05
IC MainBoard: CPU: MSD3463GLAT-W2, SPI Flash: 25Q64BSIG, Audio: TPA3110D2
Tuner: CP + SAT
LT-50T450F Specifications
GOLDSTAR LT-50T450F
General recommendations for TV LCD LED repair
Possible malfunctions
- TV GOLDSTAR LT-50T450F does not turn on, does not respond to the remote control and control panel buttons, does not light up or blink indicators.
In such cases, you should start looking for a malfunction in the 5800-L5L017-W300 power supply circuits. It is necessary to make sure that its output voltages are present and, if they are completely absent, check the power switches and rectifier diodes for a possible short circuit.
In case of any breakdowns in the secondary circuits, the converter can operate in an emergency mode of a short circuit, and in the event of a short circuit in the power elements of the primary circuit, the mains fuse or the current sensor in the source of the key often breaks off.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements, which can disable it in key mode, or provoke an excess of the maximum current or voltage values. These can be circuits supplying the PWM controller, damper or frequency setting circuits, or OOS (negative feedback) elements in the stabilization circuit. PWM controllers (PWM) TEA1733, in the absence of external damage and a short circuit between the terminals, are checked by replacing them with a known good one.
- There is no picture, but there is sound and reaction to commands from the remote control. Or the image appears immediately after switching on and disappears.
The backlight of the matrix (LED panel) is usually faulty in these cases. Often the cause of a malfunction is the lack of current in the LED circuit, for example, their open or short circuit, or a violation of the contact connections of the connectors.
To test the LED strips, in order to open all the transitions of the LEDs, several tens of volts or more are needed, it is best to use a current source for such purposes. The breakage of several PN junctions connected in series cannot be detected with a multimeter or tester. In such cases, it is necessary to open the panel and check each LED. If your multimeter cannot open the LED junctions in forward bias, you can sometimes detect the presence of a protective zener diode PN junction by connecting the probes in the opposite direction. If the zener diode is cut off or broken in K / Z, then the LED is faulty and needs to be replaced.
- 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 5800-A6M33G-0P20 motherboard should begin with checking the stabilizers and power converters required to power the microcircuits and matrix. If necessary, you should update or replace the software (software). Complex repair of MB (SSB) is possible only in a service center with the necessary equipment. Checking or replacing CPU elements: MSD3463GLAT-W2, SPI Flash: 25Q64BSIG, Audio: TPA3110D2 requires the necessary training and professional skills to repair modules at the component level. Problems associated with the use of BGA soldering technologies can sometimes be diagnosed by the warm-up method.
If there is no tuning for terrestrial or cable TV channels, you should make sure that the software is correct, as well as that the supply voltages on the CP + SAT tuner pins are in line. It is also necessary to check with an oscilloscope the presence of pulses of data exchange between the tuner and the processor via the I2C bus.
We remind users again! Attempts to repair the GOLDSTAR LT-50T450F TV without proper qualifications and necessary experience can lead to its complete non-repairability!

Reduce the backlight current in TVs with 168P-L5L017-W3 (5800-L5L017-W300) power supplies as follows. The current sensors in each of the three channels consist of two 3.3 Ohm resistors connected in parallel at the sources of the Q403-Q405 switches. You can reduce the backlight current by about 30% by replacing one of the 3.3 Ohm resistors by 10 Ohm in each channel.

 The appearance of MainBoard 5800-A6M33G-0P20 is shown in the figure below:
5800-A6M33G-0P20
Main features of the GOLDSTAR LT-50T450F device:
Installed matrix (LED panel) LC490DUJ-SHA2.
To power the backlight LEDs, a converter combined with a power supply is used, controlled by an OZ9903GN PWM controller.
https://1.bp.blogspot.com/-6JKGgeB0Wis/XfpHI7IJXII/AAAAAAAAjOU/7odfI7CRlTYBPFSUK8LuNd0ynYps4KELACK4BGAYYCw/s1600/5800-A6M33G-0P20_DCE.jpg
The formation of the necessary supply voltages for all nodes of the GOLDSTAR LT-50T450F TV is carried out by the 168P-L5L017-W3 power module, or its analogs using TEA1733 microcircuits.
MainBoard - the main board (motherboard) is a 5800-A6M33G-0P20 module, using CPU chips: MSD3463GLAT-W2, SPI Flash: 25Q64BSIG, Audio: TPA3110D2 and others.
The CP + SAT tuner provides TV reception and channel tuning.
TV GOLDSTAR LT-50T450F with LCD LC490DUJ-SHA2, diagonal size 50 "(127 cm) 16: 9. The required brightness of the screen 350 cd / m2 is provided by LED backlighting. Contrast, as the ratio of maximum brightness to minimum, is 900: 1. The technology of production of the screen of this TV model is realized with LED backlighting. The design and technical capabilities of the TV provide viewing of broadcasts and movies in high quality HD at a resolution of 1920x1080 pixels in graphic resolution according to the standard 1080p (Full HD). Supported media file formats: MP3, WMA, MPEG4, MKV, JPEG.
Speaker power 16 W (2x8 W) is provided by two speakers. Uses NICAM stereo processing system and Sound Surround function.
External interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, VGA, HDMI x3, MHL, USB x2. A headphone output is provided.
The digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2, DVB-S2 standards.
Dimensions: with stand 1103x686x264 mm, without stand 1103x645x86 mm.
Attention! The LC490DUJ-SHA2 panel of the GOLDSTAR LT-50T450F 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.

Posted By: FRANK at 05:42
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