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, 21 August 2020

REPAIRING / SERVICING TV ROLSEN RL-20D40

Technical description and composition of the ROLSEN RL-20D40 TV, panel type and modules used. The composition of the modules.
ROLSEN
Model: RL-20D40
Chassis / Version: PLVM01
Panel: LC201V02
MainBoard: PLVM01
IC MainBoard: CPU: VCT49X3R F2 208010.000, MLT015GF; DC / DEC: 2576-3.3, 8050SD, AS1117 / 1.8; 2.5; 3.3 /, EPROM - A29040BL, EEPROM - A51CS, A21CS; Sound - TDA7266 P15V330WE
Tuner: TECH2949PS40A
RL-20D40 Specifications
ROLSEN RL-20D40
General recommendations for TV LCD repair
Repair of electronic equipment usually begins with its external examination and diagnosis of a malfunction. In this case, you should inspect all internal elements of the PLVM01 chassis, as well as external hull ones. Based on visible changes in the state of components, it is usually possible to determine the further direction of troubleshooting and localization of the defect before taking the necessary measurements. In some cases, defective elements are visible with the naked eye, for example, charred resistors or swollen sintered capacitors, or electrolytic ones in rectifier filters. The formed ring cracks in the soldering of the terminals of transformers or heating circuit elements are also frequent sources of many malfunctions with a variety of external manifestations.
In the absence of any signs of operability, when the ROLSEN RL-20D40 does not turn on and does not signal anything with the control lamps on the panel, there is a possibility of a malfunction of the TV power supply module. The power supply regulator of the control processor on the motherboard may also be faulty with the same manifestations. In general, first of all, it is necessary to check the electrolytic capacitors of the filters of the secondary rectifiers and the fuse at the mains input. If it is cut off, then the diodes of the rectifier bridge and the key transistor of the converter, which can be located either on a separate heatsink or integrated with a PWM controller into a common microcircuit, should be checked for a breakdown of PN junctions. Options are possible.
If a breakdown of the power switch is detected, it should be remembered that in a switching power supply (SMPS) it does not fail by itself without reasons that should be looked for by checking other elements of the primary circuit - electrolytic capacitors, a PWM controller, which can only be checked replacement, as well as other semiconductor elements (diodes, transistors, zener diodes).
Sometimes the ROLSEN RL-20D40 TV does not have an image, but there is sound, or the image appears and immediately disappears. In this case, there is a high probability of a malfunction of the backlight converter, or the lamps themselves, which can be checked by replacing. In such cases, it is necessary to make sure that all electrolytic capacitors of the filter are in good working order for the power supply of the inverter itself, including in the power supply unit (power supply unit). When turning off the protection in order to ensure the possibility of diagnosing a malfunction, special care should be taken, and after all repair work is completed, it is imperative to restore the circuits and the operation of the inverter protection for further safe operation of the TV.
When trying to repair the motherboard, you should first check the serviceability of linear stabilizers or microcircuit power converters and, if necessary, update the software (software). In some cases, the elements of the MB (SSB) board require checking or replacing (if necessary) - CPU: VCT49X3R F2 208010.000, MLT015GF; DC / DEC: 2576-3.3, 8050SD, AS1117 / 1.8; 2.5; 3.3 /, EPROM - A29040BL, EEPROM - A51CS, A21CS; Sound - TDA7266 P15V330WE. In cases where a BGA processor is used, its malfunction is usually detected by a local warm-up method.
Attention to users! Self-repair of the ROLSEN RL-20D40 TV without appropriate qualifications and experience can lead to its complete non-repairability!
https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1Gx_Pfr8I9U3sKeqr5UYaJVBjGFjHnzR0wf8NZzdEcgCCzUrI3FpUTLp8GW7yeJ3PHIMJDa59zQa5sRhG2aCyHCX1uEjNVkZLkvZQHC7Q6mSrZRC3BB7hkqTC1dbfziy6htgqPkGx864/s1600/PLVM01_DPPB10254S_DCE.jpgAdditional MainBoard Repair
The appearance of the MainBoard PLVM01 is shown in the figure below:
PLVM01
The main features of the ROLSEN RL-20D40 device:
Installed matrix (LCD-panel) LC201V02.
The necessary supply voltages for all nodes of the ROLSEN RL-20D40 TV are provided by a switching power supply.(See voltages in picture)
MainBoard - the main board (motherboard) is a PLVM01 module, using CPU chips: VCT49X3R F2 208010.000, MLT015GF; DC / DEC: 2576-3.3, 8050SD, AS1117 / 1.8; 2.5; 3.3 /, EPROM - A29040BL, EEPROM - A51CS, A21CS; Sound - TDA7266 P15V330WE and others.
Tuner TECH2949PS40A provides reception of TV programs and tuning to channels.
Additional technical information about the panel:
Brand: LG.Philips LCD
Model: LC201V02-SDA3
Type: a-Si TFT-LCD, Panel
Diagonal size: 20.1 inch
Resolution: 640x480, VGA
Display Mode: IPS, Normally Black, Transmissive
Active Area: 408x306 mm
Surface: Antiglare, Hard coating (3H)
Brightness: 450 cd / m²
Contrast Ratio: 800: 1
Display Colors: 16.7M (8-bit)
Response Time: 12/13 (Tr / Td)
Frequency: 60Hz
Lamp Type: 6 pcs CCFL Without Driver
Signal Interface: CMOS (1 ch, 8-bit), 41 pins
Voltage: 12.0V


ROLSEN RL-20D40 TV with LCD display LC201V02, diagonal size 20 "4: 3. The brightness of the screen is 450 cd / m2 provided by CCFL (EEFL) fluorescent lamps. Contrast, as the ratio of maximum brightness to minimum, is 800: 1 The input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC.Graphic processing and digital signal shaping takes place in the 480i, 480p, 576i, 576p standards.
Speaker power 6 W (2x3W) is provided by two speakers. The NICAM STEREO audio processing system is used.
External interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, audio x2, S-Video, SCART, RGB, VGA. A headphone output is provided. To connect a computer or laptop to this TV model, use the VGA (D-Sub 15) connector on the TV case, this interface supports resolutions: 640x480.
Dimensions: with stand 510x480x240 mm, without stand 510x435x86 mm.
TV weight: with stand: 9.5 kg, without stand: 8.5 kg.
Attention! ROLSEN RL-20D40 LCD TV panel LC201V02 is its most expensive component.
Avoid hitting the glass and putting pressure on the screen surface to avoid irreversible damage to the LCD panel!