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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Monday 9 March 2020

REPAIR / SERVICING TV SONY KDL-40W905A

Technical description and composition of the TV SONY KDL-40W905A, type of panel and applicable modules. The composition of the modules.
SONY LED
Model: KDL-40W905A
Chassis / Version: RB1G
Panel: YLV4021-02N
LED backlight: L / R 61.P8902G001 13524C (LB)
T-CON: 1-888-061-11 A-1919-760-A (173410711) - YJK01001
LED driver (backlight): ST4055LD-S03 REV1.0
Power Supply (PSU): APS-343 (CH) - 1-888-119-11 - 1-474-484-11 - 147448411
MainBoard: 1-888-101-31 (173415631) Y200A420A
IC MainBoard: CPU: CXD4739GB; NAND Flash: TC58DVG3S0ETA00 (TC58NVG3S0FTAI0)
Control: Wi-fi: module J20H069; IR: 1-887-520-31 & 1-887-030-11 (1-733-693-11)
Appearance
SONY KDL-40W905A
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The SONY KDL-40W905A TV does not turn on and does not show any signs of turning on at all. There are no reactions to the control buttons or the remote control.
Most likely, in this case, the main switching power supply (IIPS) APS-343 is faulty. It is necessary to measure its output voltages and, if they are absent, to check for short-circuit probabilities in the converters, power switches and rectifier diodes.
In case of breakdowns of semiconductors in secondary circuits, any converter can usually work normally in emergency short circuit mode. There are no output voltages. And with a short circuit in the power elements of the primary circuit, as a rule, the mains fuse breaks and less often the current sensor at the source of the key.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke an excess of the maximum current or voltage. It can be supply, damper circuits, or elements of OOS (negative feedback) stabilization. The reason for the breakdown of the power switch may be its PWM controller (PWM), which is usually checked by replacing a known-good one.
- 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.
As a rule, in such cases there is no display 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.
When diagnosing, it is necessary to take into account that it is impossible to check the open in the chain of LED lines without disassembling the panels using a tester or multimeter. To open all PN junctions connected in series, a voltage of the order of several tens of volts is required, and ideally, a current source. By opening the panel, each LED can be checked separately. Typically, Chinese multimeters light up a single 3-volt LED, if you connect probes in the forward direction to it. In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of health. In the event of a LED malfunction, its zener diode will either be cut off or broken into short-circuit.
- The TV does not enter the operating mode, does not respond to the remote control. The indicator on the front panel lights constantly or blinks.
Repair or diagnostics of the motherboard 1-888-101-31 should begin by checking the stabilizers and power converters needed to power the microcircuit 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: CXD4739GB; NAND Flash: TC58DVG3S0ETA00 (TC58NVG3S0FTAI0) 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.

Attention! For users and owners of KDL-40W905A TVs who do not have the appropriate qualifications, knowledge and experience, we strongly recommend against attempting self-repair in order to avoid negative consequences that could lead to complete non-serviceability of the device.



The appearance of MainBoard 1-888-101-31 is shown in the figure below:
1-888-101-31
1-888-101-31 can be used in TVs:
SONY KDL-42W808A (Panel LC420EUF (FF) (P2)), SONY KDL-46W905A (Panel YLV4621-02N), SONY KDL-40W905A (Panel YLV4021-02N).
The appearance of the power supply
Main features of the device SONY KDL-40W905A:
Installed matrix (LED panel) YLV4021-02N.
The matrix control uses the Timing Controller (T-CON) 1-888-061-11.
The LED driver ST4055LD-S03 is used to power the backlight LEDs.
The formation of the necessary supply voltages for all nodes of the SONY KDL-40W905A TV is carried out by the APS-343 power module, or its analogs.
MainBoard - the main board (motherboard) is a module 1-888-101-31, using CPU chips: CXD4739GB; NAND Flash: TC58DVG3S0ETA00 (TC58NVG3S0FTAI0) and others.


Posted By: FRANK at 02:48
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