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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Friday 1 May 2020

REPAIR / SERVICING TV MYSTERY MTV-4225LT2

Technical description and composition of the MYSTERY MTV-4225LT2 TV, type of panel and applicable modules. The composition of the modules.
MYSTERY LED
Model: MTV-4225LT2
Chassis / Version: MT31LB / V2N08
Panel: LVF420CMOT - E18.V1
LED backlight: TCL-462C750 (B3310) -6EA-L
T-CON: V420HJ2-P01 REV.C2
LED driver (backlight): 40-R32E42-DRD1XG
PWM LED driver: OB3362RP
Power Supply (PSU): 40-E081C5-PWI1XG
PWM Power: OB2273A
MOSFET Power: 13A650
MainBoard: 40-T31TOT-MAB2HG
IC MainBoard: Spi Flash: Winbond 25Q64FVSIG
Tuner: RF221ZN V4D17AA
Technical Specifications MTV-4225LT2
MYSTERY MTV-4225LT2
General repair guidelines for TV LCD LED
Possible malfunctions
- The MYSTERY MTV-4225LT2 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.
Most often, with such manifestations, the main power module 40-E081C5-PWI1XG is found to be faulty. It is necessary to verify the presence of its output voltages and, if they are completely absent, check the power switches (13A650) and rectifier diodes for a probable short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during a short circuit in the 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 OB2273A, in the absence of visible damage or frank fault between the terminals, are checked by replacing with new, or obviously working.
- There is no image, but there is sound and reaction to the remote control. Or for a second, the image may appear immediately after switching on.
The most likely in these cases is a malfunction of the LED backlight. The reason can be both in the power supply of the LEDs, in their serviceability (breakdown or breakage), as well as in the violation of the contact connections of the LED strips.
To check the health in the LED circuit, it is better to use a current source with a maximum voltage of 200V. We do not recommend using any voltage sources for this purpose. You can check each LED individually with a simple Chinese multimeter (powered by 9 volts) in the P-N-junction test mode. If you connect the red probe of the multimeter to the anode of the LED, and the black to its cathode, then the 3-volt LED will light up slightly, and in the opposite direction you can detect the transition of the emergency zener diode. A zener diode PN junction indirectly indicates a LED-a
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the 40-T31TOT-MAB2HG 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 Spi Flash elements: Winbond 25Q64FVSIG 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 malfunction of the tuner RF221ZN V4D17AA is established after checking the software and all the supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be controlled by an oscilloscope.
We recommend the owners of the MTV-4225LT2 TV for repair only to qualified specialists with the necessary work experience! Self-repair attempts without the appropriate knowledge and skills can lead to irreversible negative consequences!
FIRMWARE FOR SPI FLASH  ----------->   MYSTERY MTV-4225LT2, Main: 40-T31TOT-MAB2HG, Panel: LVF420CMOT - E18.V1



 To reduce the backlight current in LED drivers with an OB3362RP (TSOP16) controller, increase the total resistance of the resistors from pin 5 (ISET) to the chassis. The maximum current in each of the four channels (in milliamps) for the Rset resistor (in kilo-ohms) is determined from the ratio 3000 * 1.2V / Rset.

Repair MainBoard
The appearance of the MainBoard 40-T31TOT-MAB2HG is shown in the figure below:
40-T31TOT-MAB2HG
40-T31TOT-MAB2HG can be used in TVs:
ERISSON 32LET40 (Panel LVW320CSOT E45 V11 T8-32T3510-LPM8), ERISSON 28LET40 (Panel LVW280CSOT E19 V2), FUSION FLTV-24T25 (Panel LVW240CMOT E12 V6), MYSTERY MTV-3227LT2 (Panel LVW320CSOT E45 V11 720p HD 1366x768), MYSTERY MTV-4225LT2 (Panel LVF420CMOT - E18.V1), SUPRA STV-LC32T662WL (Panel LWV320CSOT E45 V16 (T8-32T3520-LPM10)).
The appearance of the power supply
Main features of the MYSTERY MTV-4225LT2 device:
Installed matrix (LED-panel) LVF420CMOT - E18.V1.
The matrix control uses the Timing Controller (T-CON) V420HJ2-P01.
The LED driver 40-R32E42-DRD1XG is used to power the backlight LEDs, it is controlled by the OB3362RP PWM controller.
The necessary supply voltages for all nodes of the MYSTERY MTV-4225LT2 television are generated by the 40-E081C5-PWI1XG power supply module, or its analogs using OB2273A microcircuits and 13A650 type power switches.
MainBoard - the main board (motherboard) is a 40-T31TOT-MAB2HG module, using Spi Flash chips: Winbond 25Q64FVSIG and others.
The tuner RF221ZN V4D17AA provides the reception of television programs and tuning to channels.
The MYSTERY MTV-4225LT2 TV with an LVF420CMOT LCD display, 42 "(107 cm) diagonal size in 16: 9 format. The required screen brightness of 300 cd / m² is provided by LED backlighting. Contrast, as the ratio of maximum brightness to minimum, is 4000: 1. The LED-panel of this TV is equipped with end LED backlighting - Edge LED.The design and technical capabilities of the TV include viewing programs and movies in high quality HD at a resolution of 1920x1080 pixels in a graphic layout according to the standard 1080p (Full HD). frequency or video signal can be processed in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats: MP3, JPEG.
The power of the sound system 16 W (2x8 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), component, VGA, HDMI x2, USB. 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, 1920x1080.
A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
Overall dimensions: With stand 642x444x209 mm, Without stand 642x398x44 mm.
Attention! The LVF420CMOT - E18.V1 panel of the MYSTERY MTV-4225LT2 LED TV is an expensive and unreliable element.
Avoid any impact on the glass and pressure on the surface of the screen to avoid damage to the LED panel!
It is also unsafe to get liquid on the screen. Sometimes one drop is enough if it flows down the glass onto the cables so that the TV becomes unrepairable.
Posted By: FRANK at 05:33
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