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 !

Wednesday, 12 February 2020

REPAIR / SERVICING TV LG 24MT48VF-PZ

Technical description and composition of the LG 24MT48VF-PZ TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 24MT48VF-PZ
Chassis / Version: LD60A MT58 / 48
Panel: V236BJ1-LE2
LED backlight: LG Innotek 23.6inch Rev0.1
LED driver (backlight): integrated into MainBoard
PWM LED driver: MP3378E
Power Supply (PSU): Adapter 19V
MainBoard: EAX66873503
IC MainBoard: CPU: LGE6351, Audio: M28720, SPI FLASH: 25L8005, Eeprom: 4G25 (24C256)
Tuner: TDJA-G301D
Technical Specifications 24MT48VF-PZ
LG 24MT48VF-PZ
General repair guidelines for TV LCD LED
Possible malfunctions
- The LG 24MT48VF-PZ TV does not turn on and does not show any signs of operability at all. There is no reaction to the remote control and control buttons from the front panel.
In some of these cases, the main switching power supply, the Adapter module, is faulty.
The owner of the TV can purchase an external power supply unit such as Adapter and repairing it is not always advisable. In any case, the simplest typical defects characteristic of most IIP schemes can be easily detected and eliminated after opening. It is necessary to measure the output voltages in its secondary circuits, and if they are completely absent, it is necessary to check the serviceability of power switches and rectifier diodes for possible breakdown (short circuit).
In case of breakdowns in the secondary circuits, the converter, as a rule, can emergency work in the short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse usually breaks.
Mos-Fet power switches, used in switching power supplies, sometimes fail due to a malfunction of any other elements that can put it out of operation in key mode or create an excess of the maximum permissible parameters of the switch. These can be elements supplying the PWM controller, frequency-setting or damping circuits, or negative feedback elements in the stabilization circuit. PWM controllers, in the absence of visible damage or explicit short-circuit between the terminals, are checked by replacing with new ones, or obviously working.
- There is no image, there is sound, it is responding to the remote control. Or immediately after turning on for a second, the image may appear and immediately disappear.
In some of these cases, the malfunction is caused by a lack of backlighting on the display. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
It is impossible to check the LED line for breaks without disassembling the panel with a multimeter or tester. For these purposes, it is necessary to open all series-connected PN junctions and a voltage of the order of tens of volts will be required, and ideally, a current source. Having disassembled the panel, it is necessary to check each LED separately. Chinese multimeters, as a rule, light up a single 3-volt LED in the forward direction. In the case of using dual 6-volt LEDs, the PN junction of its protective zener diode can serve as a health indicator. In faulty LEDs, the zener diode will either be cut off or broken into short-circuit.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the EAX66873503 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). Complex repair of MB (SSB) is possible only in the conditions of a service center with the necessary equipment. Checking or replacing CPU elements: LGE6351, Audio: M28720, SPI FLASH: 25L8005, Eeprom: 4G25 (24C256) 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 warming up.
The TDJA-G301D tuner malfunction is established after checking the software and all supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be controlled by an oscilloscope.
TV users and owners must remember that attempts to self-repair a LG 24MT48VF-PZ TV without the appropriate qualifications and the necessary experience can lead to serious negative consequences!
FIRMWARE  SPI FLASH LG 24MT48VF-PZ LD60A MT58/48, Main: EAX66873503, Panel: V236BJ1-LE2


 To reduce the backlight current in LED drivers with the MP3378E PWM controller, it is necessary to proportionally increase the total resistance of the resistors from pin 3 (RISET) to the chassis. Calculation of current in milliamperes and resistance in kilo-ohms 977 / Rset for each channel. Parallel channels are summed. For example, for four parallel channels and a RISET 10 KOhm resistance, the total current will be 97.7 * 4 = 391 mA.


More details on this page


 The appearance of the MainBoard EAX66873503 is shown in the figure below:
EAX66873503
EAX66873503 can be used in TVs:
LG 22LH450V PZ (Panel HM215EUN-SLMP1 - 41XX), LG 24LH450U (Panel V236BJ1-LE2A), LG 28LH451U (Panel HC275EXN-ABVP1-41XX), LG 20MT48VF 20MT48VF-PZ (Panel 1366x768 720p HD).
Main features of the device LG 24MT48VF-PZ:
Installed matrix (LED-panel) V236BJ1-LE2.
To power the backlight LEDs, a converter is used, combined with the EAX66873503 main board, controlled by the MP3378E PWM controller.
To power all the internal components of the LG 24MT48VF-PZ TV, an external adapter 19V type source is used.
MainBoard - the main board (motherboard) is an EAX66873503 module using CPU chips: LGE6351, Audio: M28720, SPI FLASH: 25L8005, Eeprom: 4G25 (24C256) and others.
The TDJA-G301D tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: CHIMEI INNOLUX
Model: V236BJ1-LE2
Type: a-Si TFT-LCD, Panel
Diagonal size: 23.6 inch
Resolution: 1366x768, WXGA
Display Mode: Super MVA, Normally Black, Transmissive
Active Area: 521.471x293.184 mm
Surface: Antiglare (Haze 1%), Hard coating (3H)
Brightness: 250 cd / m²
Contrast Ratio: 3000: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 8.5 (G to G)
Frequency: 60Hz
Lamp Type: WLED Without Driver
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V
Posted By: FRANK at 01:41
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