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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Saturday 21 March 2020

REPAIR / SERVICING TV BBK LT4214S

Technical description and composition of the BBK LT4214S TV, type of panel and applicable modules. The composition of the modules.
BBK
Model: LT4214S
Chassis / Version: Ver1
Panel: LC420WX7 Sl A1
Inverter (backlight): LC420WX7 M / S Rev1.3
Trans Inverter: BET2544-42L3
Power Supply (PSU): HLP-45A01
PWM Power: LM2576T-ADJ
MOSFET Power: 24N50,
MainBoard: RSAG7.820.1037 Ver C LCD4233EU
IC MainBoard: TPA3101D2, TMDS141A,
Tuner: TDQ-6FT / W126H
Technical Specifications LT4214S
BBK LT4214S
General recommendations for repairing TV LCD
Possible malfunctions
- BBK LT4214S does not turn on, the indicators on the front panel do not light or flash. The TV does not respond to the control buttons and the remote control.
With such manifestations, the HLP-45A01 power module usually fails. It is necessary to measure the secondary output supply voltage, and in case of their absence, check the serviceability of the power switches (24N50,) of the converters and rectifier diodes for a short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during short circuit in the power elements of the primary circuit, the main fuse usually breaks.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, power supply, frequency-setting, damper ... as well as elements of the Negative Stabilization Feedback. PWM chip LM2576T-ADJ can also cause a malfunction of the power switch of the converter and is checked by replacement.
- There is no image, but there is sound and reaction to commands from the remote control. Or the image appears immediately after turning on and disappears.
These manifestations can be triggered by a power module, or by defects in the inverter, as well as a distortion of the currents in the lamps due to their uneven wear. If all the electrolytic capacitors of the filter according to the inverter power supply are serviceable, you should make sure that the lamps are working, then you need to check the converter keys and the secondary windings of the transformers.
If in diagnosing a malfunction, it is necessary to disable the inverter protection, there is a risk of failure of the power elements of the inverter, and special care is required during work, and after they are finished, it is necessary to restore the protection circuits for further safe operation of the TV by the owner in normal mode.
- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the LCD4233EU motherboard should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (software). In cases of attempts to repair the MB (SSB) board, it is necessary to check the health of its elements - TPA3101D2, TMDS141A, which may require replacement with new ones. If a BGA processor is installed, there is a possibility of a violation of the soldering of the contacts of its conclusions with the board (it is diagnosed by heating).
If a TDQ-6FT / W126H tuner is suspected of malfunction, first of all, it is necessary to verify the correctness of the software, as well as the presence of the necessary supply voltage levels and data exchange pulses with the processor via the I2C bus on the corresponding tuner pins.
Once again, remind users! Attempts to self-repair a BBK LT4214S TV without the appropriate qualifications and the necessary experience can lead to its complete unrepairability!



The appearance of the MainBoard RSAG7.820.1037 is shown in the figure below:
RSAG7.820.1037
RSAG7.820.1037 can be used in TVs:
BBK LT2614S (Panel V260B1-L02), BBK LT3214S (Panel LC320W01 (SL)(A1)), BBK LT4214S (Panel LC420WX7 Sl A1), BBK LT3215S (Panel LC320WX3 (SL)(C1)), BBK LT4014S (Panel LTA400WT-L17), DAEWOO DLP-26H1C (Panel V260B1-L02).
The appearance of the power supply
Main features of the BBK LT4214S device:
Installed matrix (LCD-panel) LC420WX7 Sl A1.
To power the backlight used inverter LC420WX7. A transformer BET2544-42L3 is installed in the inverter converter.
The necessary supply voltages for all nodes of the TV BBK LT4214S are generated by the HLP-45A01 power module, or its analogs using LM2576T-ADJ microcircuits and 24N50 type power switches,.
MainBoard - the main board (motherboard) is a RSAG7.820.1037 module, using TPA3101D2, TMDS141A, and others.
The TDQ-6FT / W126H tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: LG.Philips LCD
Model: LC420WX7-SLA1
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: 1000: 1
Display Colors: 16.7M (8-bit), CIE1931 73%
Response Time: 10 (Tr + Td); 5 (G to G)
Frequency: 60Hz
Lamp Type: EEFL Embedded (Inverter)
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V

BBK LT4214S LCD TV with LC420WX7 LCD, 42 "(106 cm) diagonal display in 16: 9 format. 500 cd / m² screen brightness is provided by CCFL (EEFL) fluorescent lamps. The ratio of maximum brightness to minimum (contrast) is 1000: 1. 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 in the standard ah 480i, 480p, 576i, 576p, 720p, 1080i.
The power of the speaker system of sound 14 W (2x7 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 x2, S-Video, component, 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, 1280x1024, 1360x768.
The power consumed by the TV in the operating mode from the network is 250 watts.
Overall dimensions: 1030x770x310 mm.
TV Weight: 28.5 kg.
Attention! The BB4 LT4214S LCD panel LC420WX7 Sl A1 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!
Posted By: FRANK at 07:53
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