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-42W807A

Technical description and composition of the SONY KDL-42W807A TV, panel type and applicable modules. The composition of the modules.
SONY LED
Model: KDL-42W807A
Chassis / Version: RB1G
Panel: LC550EUF (FF) (P2)
LED backlight: Edge LED
LED driver (backlight): integrated into MainBoard
PWM LED driver: CXA3854M-T6
MOSFET LED driver: MDF3N50
Power Supply (PSU): APS-342 / B 1-888-356-21 GL2E
PWM Power: CXA3810M (PWM), MIP2H2 (Stb)
MOSFET Power: KF7N50F, TK15A50D
MainBoard: 1-888-101-31 (173415631)
IC MainBoard: CPU: CXD4739GB; NAND Flash: TC58DVG3S0ETA00
Technical Specifications KDL-42W807A
SONY KDL-42W807A
General repair guidelines for TV LCD LED
Possible malfunctions
- SONY KDL-42W807A does not turn on, the indicators on the front panel do not light up and do not blink. The TV does not respond to the control buttons and the remote control.
In some of these cases, a malfunction is detected in the APS-342 power module. In the absence of the necessary supply voltages in the secondary circuits of the converters, it is necessary to check the power switches (KF7N50F, TK15A50D) and rectifier diodes for a possible partial or complete breakdown.
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 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. These can be circuits supplying the PWM controller, damping or frequency-setting circuits, or elements of OOS (negative feedback) in the stabilization circuit. PWM controllers (PWM) CXA3810M (PWM), MIP2H2 (Stb), in the absence of external damage and short circuit between the terminals, are checked by replacing with obviously good ones.
- 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 most of these cases, a malfunction is detected in the nodes and backlight elements of the LED panel. Usually the cause of the malfunction is in the breakage of the LEDs, or in the connectors of the LED strips, but sometimes the LED driver also turns out to be faulty.
When trying to detect a break in the LED lines, it should be taken into account that it is difficult to do this without disassembling the panel. For example, a current source is needed to open PN junctions connected in series.
- 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). In cases of complex repairs of MB (SSB) and with the necessary skills and equipment, sometimes it may be necessary to replace its CPU chips: CXD4739GB; NAND Flash: TC58DVG3S0ETA00 and other possible malfunctioning components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
Attention! For users and owners of KDL-42W807A TVs who do not have the appropriate qualifications, knowledge and experience, we categorically do not recommend attempting self-repair in order to avoid negative consequences that could lead to complete non-serviceability of the device.

Service manual / Schematic Diagram -------------->   Sony KDL-42W807A chassis RB1G


psu  / Schematic Diagram -------------->   APS-342/B Power Supply schematic diagram



 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-42W807A:
Installed matrix (LED-panel) LC550EUF (FF) (P2).
To power the backlight LEDs, a converter is used, combined with the main board 1-888-101-31, controlled by the CXA3854M-T6 PWM controller. As power elements of the LED driver, keys of the MDF3N50 type are used.
The necessary supply voltages for all nodes of the SONY KDL-42W807A TV are generated by the APS-342 power module or its analogs using CXA3810M (PWM), MIP2H2 (Stb) microcircuits and power switches of the KF7N50F, TK15A50D type.
MainBoard - the main board (motherboard) is a module 1-888-101-31, using CPU chips: CXD4739GB; NAND Flash: TC58DVG3S0ETA00 and others.
Additional technical information about the panel:
Brand: LG Display
Model: LC550EUF-FFP2
Type: a-Si TFT-LCD, Panel
Diagonal size: 55 inch
Resolution: 1920x1080, FHD
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 1209.6x680.4 mm
Surface: Antiglare, Hard coating (2H)
Brightness: 380 cd / m²
Contrast Ratio: 1400: 1
Display Colors: 16.7M / 1.06B (8-bit / 8-bit + Dithering), CIE1931 72%
Response Time: 5 (G to G); 8 (MPRT)
Frequency: 120Hz
Lamp Type: WLED Without Driver
Signal Interface: V-by-One 4 lane, 92 pins
Voltage: 12.0V
Posted By: FRANK at 03:56
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