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 15 August 2020

REPAIRING / SERVICING TV ROLSEN RL-24L1004UTZC

Technical description and composition of the ROLSEN RL-24L1004UTZC TV, panel type and modules used. The composition of the modules.
ROLSEN LED
Model: RL-24L1004UTZC
Chassis / Version: RSAG7.820.4288
Panel: 24 inch
LED driver (backlight): integrated into PSU
PWM LED driver: OZ9998GN
MOSFET LED driver: AOD444
Power Supply (PSU): RSAG7.820.2256
PWM Power: NCP1271A
MainBoard: RSAG7.820.4288 / ROH TG128134T9
Tuner: SUT-RE201ZN
RL-24L1004UTZC Specifications
ROLSEN RL-24L1004UTZC
General recommendations for TV LCD LED repair
Possible manifestations of defects
- ROLSEN RL-24L1004UTZC does not turn on and does not show any signs of operability at all. Does not blink indicators and does not respond to control buttons.
With similar manifestations, a malfunction is most likely found in the RSAG7.820.2256 power module. Its output voltages should be measured and, in their absence, the serviceability of the power switches and rectifier diodes in the converters should be checked for possible breakdown.
In case of any breakdowns in the secondary circuits, the converter can operate in an emergency mode of a short circuit, and with a short circuit in the power elements of the primary circuit, the mains fuse or the current sensor at the source of the key is often cut off.
Mos-Fet power switches used in switching power supplies sometimes fail due to a malfunction of any other elements that can disable it in the key mode, or create an excess of the maximum permissible key parameters. These can be elements supplying a PWM regulator, frequency setting or damper circuits, or elements of negative feedback in the stabilization circuit. PWM controllers NCP1271A, in the absence of visible damage or outright short circuits between the terminals, are checked by replacing them with new ones, or knowingly working properly.
- There is no image, there is sound, it reacts to the remote control. Or, immediately after switching on for a second, the image may appear and immediately disappear.
The malfunction in most of these cases is found in the nodes and elements of the LED panel backlighting. The reason may 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.
It should be remembered that it is not possible to determine an open circuit in the LED lines without disassembling the panels using a tester or multimeter without an additional device, for example, a current source. To open all PN junctions connected in series at once, a voltage of several tens of volts may be required. Then you need to open the panel and check each LED separately with a multimeter. If the capabilities of your multimeter do not allow opening the LED in the forward direction or dual LEds are used, then the PN transition of the emergency zener diode can indirectly serve as an indicator of serviceability. In the event of a malfunction of the LED-a, the PN-junction of the zener diode will either be cut off or broken through in the SC.
- The TV does not turn on, the indicator signals the standby or operating mode, or blinks.
Repair or diagnostics of the RSAG7.820.4288 motherboard should begin with checking the stabilizers and power converters necessary to power the microcircuits and matrix. If necessary, you should update or replace the software (software).
If there is no tuning to channels of terrestrial or cable television, you should make sure that the software is correct, as well as that the supply voltages on the terminals of the SUT-RE201ZN tuner match. It is also necessary to check with an oscilloscope the presence of pulses of data exchange between the tuner and the processor via the I2C bus.
Attention to TV owners! Attempts to repair ROLSEN RL-24L1004UTZC on your own are not recommended by the manufacturer and can lead to serious negative consequences!


The appearance of the MainBoard RSAG7.820.4288 is shown in the figure below:


External view of the power supply
Main features of the ROLSEN RL-24L1004UTZC device:
Installed matrix (LED-panel) 24 inch.
To power the backlight LEDs, a converter combined with a power supply is used, controlled by an OZ9998GN PWM controller. The keys of the AOD444 type are used as power elements of the LED driver.
The formation of the necessary supply voltages for all nodes of the ROLSEN RL-24L1004UTZC TV is carried out by the RSAG7.820.2256 power module, or its analogs using NCP1271A microcircuits.
MainBoard - the main board (motherboard) is an RSAG7.820.4288 module.
The SUT-RE201ZN tuner provides reception of television programs and tuning to channels.
ROLSEN RL-24L1004UTZC TV with LCD 24, 24 "(61 cm) diagonal in 16: 9 format. The required screen brightness of 300 cd / m² is provided by LED backlighting. Dynamic contrast ratio of 150,000: 1 is achieved by a special control of LED operation. The LED panels of this TV are equipped with edge LED backlighting.It is possible to view images in high quality HD at a resolution of 1366x768 pixels in a graphic resolution of 720p (HD Ready) .Input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC Graphic processing and digital signal shaping takes place in 480i, 480p, 576i, 576p, 720p, 1080i, 1080p standards Supported multimedia file formats: MP3, WMA, MPEG4, MKV, JPEG.
Speaker power 4 W (2x2 W) is provided by two speakers. Uses NICAM stereo processing system and Sound Surround function.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), component, SCART, VGA, HDMI x2, USB. A headphone output is provided. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector on the TV case is used, this interface supports resolutions: 640x480, 800x600, 1024x768, 1360x768.
The digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
The power consumed by the TV in operating mode from the mains is 36 W.
Dimensions: with stand 564x422x181 mm, without stand 564x381x52 mm.
TV weight: 4.6 kg.
Attention! The ROLSEN RL-24L1004UTZC 24 inch LED TV panel is an expensive and unreliable element.
Do not allow any impact on the glass and pressure on the screen surface to avoid damage to the LED panel!
It is also unsafe for liquid to spill onto the screen. Sometimes one drop is enough if it drips down the glass onto the cables to make the TV unrepairable.