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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All posts are presented here for informative, historical and educative purposes as applicable within fair use. NOTHING HERE IS FOR SALE !

Thursday 23 July 2020

SAMSUNG LT20A350 LCD TV MONITOR TROUBLESHOOTING, FACTORY MODE AND SERVICE MODE

 

Samsung LT22A350, LT23A350, LT24A350, LT20A350, LT22A550, LT23A550, LT24A550, LT27A550.  Chassis: WDS2, WDS4

  Always respect voltages. While some may not be dangerous in themselves, they can cause unexpected reactions that are best avoided. Before reaching into a powered TV set, it is best to test the high voltage insulation. It is easy to do, and is a good service precaution.

It makes sense to avoid exposure to electrical shock.  While some sources are expected to have a possible dangerous impact, others of quite high potential are of limited current and are sometimes held in less regard.

Leakage Current Test

With the unit completely reassembled, plug the AC line cord directly into a 120V AC outlet. With the unit’s AC switch first in the ON position and then OFF, measure the current between a known earth ground (metal water pipe, conduit, etc.) and all exposed metal parts, including: metal cabinets, screwheads and control shafts.
The current measured should not exceed 0.5 milliamp.
Reverse the power-plug prongs in the AC outlet and repeat the test.

Troubleshooting

No Power

- The LEDs on the front panel do not work when connecting the power cord.
- The SMPS relay does not work when connecting the power cord.
- The units appears to be dead.

The IP relay or the LEDs on the front panel does not work when connecting the power cord if the cables are
improperly connected or the Main Board or SMPS is not functioning. In this case, check the following:
- Check the internal cable connection status inside the unit.
- Check the fuses of each part.
- Check the output voltage of SMPS.
- Replace the Main Board.

No Video (Analog PC signal)

- Check the PC source
- Check the Arsenal, Check the Main Chipset.
- This may happen when the LVDS cable connecting the Main Board and the Panel is disconnected.

No video (HDMI 1, 2, 3, 4 - Digital signal)

Audio is normal but no picture is displayed on the screen.

- Check the HDMI source.
- Check the HDMI switch, Check the Main Chipset.
- This may happen when the LVDS cable connecting the Main Board and the Panel is disconnected.

No Video (Tuner_CVBS)

- Audio is normal but no picture is displayed on the screen.

- Check the Tuner CVBS source.
- Check the Tuner, Check the Main Chipset.
- This may happen when the LVDS cable connecting the Main Board and the Panel is disconnected.

No Video (Tuner DTV)

- Audio is normal but no picture is displayed on the screen.

- Check the DTV source.
- Check the Tuner, Check the Main Chipset.
- This may happen when the LVDS cable connecting the Main Board and the Panel is disconnected.

No Video (Video CVBS)

- Audio is normal but no picture is displayed on the screen.

- Check the Video CVBS source
- Check the Main Chipset.
- This may happen when the LVDS cable connecting the Main Board and the Panel is disconnected.

No Video (Component)

- Audio is normal but no picture is displayed on the screen.

- Check the Component source
- Check the Main Chipset.
- This may happen when the LVDS cable connecting the Main Board and the Panel is disconnected

No Sound

- Video is normal but there is no sound..

- When the speaker connectors are disconnected or damaged.
- When the sound processing part of the Main Board is not functioning.
- Speaker defect.

Entering Factory Mode

To enter ‘Service Mode’ Press the remote -control keys in this sequence :
- If you do not have Factory remote – control.

Power Off > Info > Menu > Mute

How to Access Service Mode

Using the Customer Remote
1. Turn the power off and set to stand-by mode.
2. Press the remote buttons in this order; POWER OFF- INFO - MENU - MUTE to turn the set on.
3. The set turns on and enters service mode. This may take approximately 20 seconds.
4. Press the Power button to exit and store data in memory.
- If you fail to enter service mode, repeat steps 1 and 2 above.
5. Initial SERVICE MODE DISPLAY State.

x How to enter the hidden factory mode.
a. into the factory mode
b. move the tap to Advanced
c. key input : 0 + 0 + 0 + 0
xx hidden menu : Advanced

Buttons operations within Service Mode

Posted By: FRANK at 02:48
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