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, 27 December 2019

REPAIRING / SERVICING TV SAMSUNG LE37R72BX

Technical description and composition of the SAMSUNG LE37R72BX TV, panel type and applicable modules. The composition of the modules.
SAMSUNG
Model: LE37R72BX
Chassis / Version: BD37EO
Panel: CLAA370WA03S
T-CON: CPT370WA03C VTII8874, AS19-HG, TPS65161, 25F512AN, EM636165TS-7G
Inverter (backlight): 4H.V1838.491 B1 370WA03S
PWM Inverter: OZ964SN, ST393, ST358
MOSFET Inverter: AO D606 (5), C5706
Trans Inverter: 6020B704007 GP-02
Power Supply (PSU): BN96-03050A
MainBoard: BN41-00758A
IC MainBoard: MT8202EG, 24C32WP, 74HC4052D, 9933B, A21SC, A81SC, AP358, MAX232ECW, MP1583DN
Tuner: BN40-00079A TCPW3001PD32S
Appearance
SAMSUNG LE37R72BX
General repair guidelines for TV LCD
Any repair of electronic equipment begins with a careful external inspection of the device and troubleshooting. In this case, you should carefully examine all the elements of the SAMSUNG LE37R72BX TV, both internal and external. Visible damage to elements can sometimes suggest directions for finding a defect even before the necessary measurements are taken. Elements with visible damage, for example, capacitors swelled up after boiling the electrolyte, charred resistors in certain nodes of the circuit, as well as ring cracks in solders will help the master to guess the causes and possible consequences of the malfunction.
Malfunctions of the BN96-03050A power supply module can be expressed in different ways, for example, SAMSUNG LE37R72BX does not turn on at all and the control lamps on its front panel do not light up and do not blink, there are no signs of operability. It is advisable to start the troubleshooting of the power supply module by checking the mains fuse. If it is torn, it is necessary to check first of all the power semiconductor elements - rectifier diodes and the power switch of the converter, which are often found in breakdown conditions in such situations.
It should be borne in mind that in the practice of repair it is extremely rare that key transistors of the N-FET type fail for no reason that should be sought by checking other components, for example, a breakdown of the key can provoke faulty elements of the damper circuits, either dried electrolytic capacitors or dangling resistors of the primary circuit of the PSU, involved in the stabilization process. In this case, all semiconductor elements of the strapping of the PWM controller chip are subject to verification, which it is desirable to verify by replacement.
In cases where the Power Factor Corrector (PFC) is used in the power supply, troubleshooting can be a bit more complicated.
Sometimes the SAMSUNG LE37R72BX 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 converter of the backlight lamps, or of the lamps themselves, which can be checked by replacement. In such cases, it is necessary to verify the serviceability of all electrolytic capacitors of the filter according to the power supply of the inverter itself, including the power supply unit (power supply unit).
In most cases, the diagnosis and repair of the 4H.V1838.491 B1 370WA03S inverter is difficult due to the organization of protection, which turns it off in emergency cases to avoid fires during short circuits or open circuits in high-voltage circuits and during depressurization of lamps. Often, repairmen block the protection circuits in order to make the necessary measurements at the control points of the inverter to identify the causes of the defect.
It should be remembered that when the protection is turned off, there is always a risk of failure of the power elements of the inverter during diagnosis. After repair, it is imperative to restore all standard converter protection circuits.
Repair or diagnostics of the BN41-00758A motherboard must be started by checking the power stabilizers. If necessary, update the software (software). Often, the MB (SSB) card must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements and replace failed chips with new ones.
Attention to users! Self-repair of a SAMSUNG LE37R72BX TV without the appropriate qualifications and experience can lead to its complete non-repairability!
One of the typical defects of a SAMSUNG LE37R72BX TV can occur in the CLAA370WA03S.
External manifestations: color distortion in the image as a negative in the image, light tones predominate. Often in such cases, the AS19-HG gamma corrector is faulty. Another indicator of this malfunction is the excessively strong heating of the AS19-HG or the deformation of its body, which in practice makes it possible to do without measuring the gradation voltage of gray.
If replacing the AS19-HG does not solve the problem, similar symptoms can cause short circuits in the column drivers of the panel, which is usually indicated by noise in the form of even vertical stripes on the screen. Drivers are in loops and cannot be replaced, then it is necessary to replace glass, or the entire panel assembly.


SCHEMATICS ---->  Samsung LE26R71B, LE26R72B, LE32R71B, LE32R72B, LE37R71B, LE37R72B, LE40R71B, LE40R72B Chassis GBD26KE - GBR40KE




 The appearance of the MainBoard BN41-00758A is shown in the figure below:
BN41-00758A
BN41-00758A can be used in TVs:
SAMSUNG LE32S71BX (Panel CLAA320WB02), SAMSUNG LE37R72BX (Panel CLAA370WA03S), SAMSUNG LE40S71B (Panel LTA400WT-L01).
The appearance of the power supply
Main features of the SAMSUNG LE37R72BX device:
Installed matrix (LCD-panel) CLAA370WA03S.
The matrix control uses the Timing Controller (T-CON) CPT370WA03C.
To power the backlight, an inverter 4H.V1838.491 is used, it is controlled by the PWM controller OZ964SN, ST393, ST358. A transformer 6020B704007 GP-02 is installed in the inverter converter. As power elements of the inverter, keys of the type AO D606 (5), C5706 are used.
The formation of the necessary supply voltages for all nodes of the SAMSUNG LE37R72BX TV is carried out by the power module BN96-03050A, or its analogs.
MainBoard - the main board (motherboard) is a BN41-00758A module, using chips MT8202EG, 24C32WP, 74HC4052D, 9933B, A21SC, A81SC, AP358, MAX232ECW, MP1583DN and others.
The tuner BN40-00079A TCPW3001PD32S provides reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: CPT
Model: CLAA370WA03SC
Type: a-Si TFT-LCD, Panel
Diagonal size: 37 inch
Resolution: 1366x768, WXGA
Display Mode: MVA, Normally Black, Transmissive
Active Area: 819.6x460.8 mm
Surface: Hard coating (3H)
Brightness: 400 cd / m²
Contrast Ratio: 1200: 1
Display Colors: 16.7M (8-bit), CIE1931 75%
Response Time: 8 (G to G)
Frequency: 60Hz
Lamp Type: 16 pcs CCFL Embedded (Inverter)
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V