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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Tuesday, 30 March 2021

REPAIRING / SERVICING TV TELEFUNKEN TF-LED32S30T2

Technical description and composition of the TELEFUNKEN TF-LED32S30T2 TV, type of panel and modules used. Module composition.
Composition Specifications
TELEFUNKEN TF-LED32S30T2
LCD TV LED TF-LED32S30T2 |

 Year of manufacture: 2014
Screen diagonal: 31.5" (80 cm)
Screen Format: 16:9
Resolution: 1366x768
Refresh rate:     50Hz
LCD panel type: CX315DLEDM
LED backlight: LED Edge LED
Support HD: 720p HD
Brightness: 250 cd/m2
Contrast: 2400:1
Viewing Angle: 178°
Pixel response time: 8 ms
Progressive scan: Yes
TV Standards: PAL, SECAM, NTSC
Digital tuner: DVB-T, DVB-T2, DVB-C
Number of channels: 1100
Teletext: 1000 page memory.
DTV formats: 480i, 480p, 576i, 576p, 720p, 1080i, 1080p
Multimedia: MP3, WMA, MPEG4, Xvid, DivX, MKV, JPEG
Audio Stereo: Yes
Sound power: 6W (2x3W)
Acoustics: two speakers
Interface: AV, audio x2, component, VGA, HDMI, USB
Headphone jack: yes
TV weight:     3.5 kg
Dimensions: with stand 729x469x168mm
without stand 729x429x76 mm
Find out more...
TELEFUNKEN TF-LED32S30T2

TELEFUNKEN LED
Model: TF-LED32S30T2

Chassis/Version: CV512H-U42

Panel: CX315DLEDM LE-32Z2

LED driver (backlight): integrated into MainBoard

PWM LED driver: BIT3267

MOSFET LED driver: ME15N10 TO-252

Power Supply (PSU): integrated into MainBoard

PWM Power: PWM SOT23-6

MOSFET Power: TO-252

MainBoard: CV512H-U42

MainBoard IC: SPI Flash: W25Q64, Audio: RDA3118E28 (TPA3110D)

MainBoard: CDT-9NT372-RD60
General recommendations for LCD LED TV repair
Possible trouble spots

- The TELEFUNKEN TF-LED32S30T2 TV set does not turn on or does not respond to the remote control.

In this case the failure may be the main power supply - AC/DC converter, elements of which in this model are located on the common MainBoard CV512H-U42. It is necessary to measure its output voltages, and in case of their absence (full or partial), it is necessary to check the serviceability of power keys (TO-252) of converters and rectifier diodes for possible short circuit.
At breakdown of semiconductors in the secondary circuits of any converter, as a rule, it can operate in the short-circuit emergency mode without output voltages, and at short circuit in the elements of the primary circuit most often the line fuse and more rarely the current sensor in the source of the key break immediately.
Breakdown of Mos-Fet switches, used in pulse sources, is often caused by failure of other elements, for example, in PWM regulator supply circuit, in frequency-retaining or damping circuits, as well as in the Negative Feedback Stabilization. PWM chips (PWM) PWM SOT23-6 are usually checked by replacing them with new ones or with ones known to be in good working order.

- No picture, sound is present and all other TV functions are working. When turned on, the picture may sometimes appear for a second.

In some of these cases, the malfunction is caused by the lack of display backlighting. The reason for this may be a break in the circuit of the LEDs, or a problem in the stabilization of their power supply.
Without a special current source it is impossible to check the line of LEDs in series, and it is not safe for them to use any voltage sources over 12v for this purpose. The only thing you have to do is to open the panel and check each LED separately. Usually Chinese multimeters with 9V power supply will light up one 3 volt LED a bit if you connect the probes to it in forward direction, red probe to anode, black probe to cathode. For twin 6-volt LEDs the PN junction of its faulty regulator can be a good indicator. If the LED is faulty, its regulator will either be broken or it will be short-circuited.

If TELEFUNKEN TF-LED32S30T2 has no picture but you have sound, often the backlight of the CX315DLEDM display simply does not work. Moreover, in LED-TVs, usually the LEDs inside the panel fail, less often the LED-driver.
In such cases you can see a faintly visible image when external light hits the screen.

To replace the LEDs requires disassembly of the LCD panel CX315DLEDM - the process requiring a master of experience and expertise. We do not recommend to perform such works by yourself to owners of TV sets and craftsmen who have no experience in LCD panel repair.


READ HOW TO REPAIR THE TV LED BACKLIGHT --------------> HERE.



If there is no image, but backlighting works - the screen becomes slightly lighter when the TV is turned on, and in the open TV you can see the light through the holes in the body of the panel.
In this case the panel may be defective - damage to the strips, cables, for example, as a consequence of moisture after an unsuccessful washing of the screen, the T-CON board (Timing Controller) may be defective. But quite often the CV512H-U42 MainBoard is faulty as well and so is the software.
Then first it is necessary to check the panel power supply voltage, fuses on the T-CON board, as well as the supply and reference voltages of the column and line drivers - VGH, VGL, Vcom.
If these measurements are within normal limits, it is necessary to trace by oscilloscope LVDS signals from MainBoard CV512H-U42, as well as synchronizing signals to driver stubs.

Filled or unsuccessfully washed LED TV screens can be restored in about half of the cases, usually, if there is no significant damage to the panel stubs and slats.


- The LED blinks or lights constantly, the TV set does not turn on, the remote control does not respond.

Repair or diagnosis of the motherboard CV512H-U42 should begin with checking the stabilizers and power converters needed to power the chips and matrix. If necessary, software (software) should be updated or replaced. If there is no possibility of replacing the MB board (SSB), you should check the serviceability of its elements - SPI Flash: W25Q64, Audio: RDA3118E28 (TPA3110D). Defective components should be replaced.

Before replacing the CDT-9NT372-RD60 tuner, if there is no tuning to the channels, first check the software and the power supply voltages on its outputs. Also make sure that the tuner and the processor can exchange data via the I2C bus.

Once again I  would like to remind the users! Trying to repair your TELEFUNKEN TF-LED32S30T2 without proper skill and experience may make your TV completely unrepairable.


DOWNLOAD SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>   Chassis CV512H-U42.

Refinement after repair of the backlight. CV512H-U42, BIT3267. Information from the master.

Reduce backlight current from 300 mA to 210 mA - removed one 1.0 Ohm resistor in the backlight current sensor (PR182, PR183, R203, PR238) on the CV512H-U42 board.
Driver current limitation. CV512H-U42, BIT3267S. General Information.

To reduce the backlight current in LED drivers with the BIT3267 controller you have to increase the total resistance of the low resistance current sensor resistors Rset, connected to pin 5 INN of the BIT3267 chip. Usually the LED backlight connector is connected to these.
The total resistance RLed can be calculated from the ratio RLed = 0.21/ILed.
On the V512H-U42 board these are resistors PR182, PR183, R203, PR238 next to diodes PD6 and PD21 (M7).
CV512H-U42 current backlight.



READ HOW TO REPAIR THE TV LED BACKLIGHT --------------> HERE.


A pdf document is included ---------->  BIT3267.
 

Many TV manufacturers are now installing a questionable thermal rating for the backlight LEDs, which has a negative effect on the longevity of the device. In half of the cases, LEDs fail after 2-3 years of operation due to overheating, usually seen by the destroyed phosphor on the body of the LEDs. The warranty period, as a rule, the LEDs still have time to work out.

Even if the maximum allowable current is within specifications the cooling of LEDs is not always sufficiently efficient, which can be seen by the traces of overheating, i.e. dark spots on textolite slats on the back side. And modern LED televisions use diodes with an external phosphor coating, which after a year or two crumbles and the crystal directly shines purple. How such a source of ultraviolet radiation can harm the health of users, no one has yet thought.

Chinese manufacturers via Aliexpress supplies diodes and LED strips in kits of any assortment, but the lucky owner of the TV pays for them and for the repair.

After replacing one or more faulty LEDs, it is useful to look at the rest carefully, if the phosphor is cracked, it is advisable to replace all the LEDs. If you measure the voltage drop on overheated LEDs, it will be slightly higher than that of adjacent less worn or new LEDs, which indirectly indicates the presence of a parasitic active resistance (ESR). Further operation of such LEDs is even more questionable.


If you reduce the current in the diodes, the power dissipation and the real operating temperature will decrease, then there is a chance that the old ones will still work.


Ways to limit the current in LED backlight drivers:

There is a lot of information on the Internet about ways to limit the current in the LED backlighting for different TVs and LED drivers. A lot of it is written plausibly but sometimes it is written by people far from electronics in order to publish any popular content on hot topics to boost web-sites ratings.

It's impossible to talk about each case separately within one article, because even similar models may have different panels and different boards with their own driver variants. But there are basic principles that are clear to craftsmen with even minimal knowledge and skill.


 

More on MainBoard Repair

The appearance of the MainBoard CV512H-U42 is shown in the figure below:




CV512H-U42.

The CV512H-U42 can be used in televisions:

DEXP H39D7000Q (Panel LC390TA2A), SUPRA STV-LC32LT0010W (Panel KM0320LDRH0037).








PWM SMPS in SOT-23-6, SOT-26, TSOP-6 packages

In the circuitry of modern switching power supplies (SMPS), PWM controllers made in small-sized planar packages with six terminals have gained wide popularity. The enclosure type designation can be SOT-23-6, SOT-23-6L, SOT-26, TSOP-6, SSOT-6. The appearance and arrangement of the pins are shown in the figure below. In this case, the code marking LD7530A is shown on the left fragment of the picture.


 

 Pin assignment:
1 - GND. (Common wire).
2 - FB. (FeedBack - Feedback). Input for controlling the duration of pulses with a signal from the output voltage. Sometimes it can be labeled COMP (input comparator).
3 - RI / RT / CT / COMP / NC - Depending on the type of microcircuit, it can be used for a frequency-setting RC circuit (RI / RT / CT), or for organizing protection, as an input of a PWM trip comparator at a threshold value at its input, specified in the document. In some types of microcircuits, this input may not be used in any way (NC - No Connect).
4 - SENSE, otherwise CS (Current Sense) - Input from the current sensor at the source of the key.
5 - VCC - Input voltage supply and start of the microcircuit.
6 - OUT (GATE) - Output for controlling the gate (Gate) of the key.

Functionally, these regulators work on the principle of the previously popular xx384x PWM microcircuits, which have proven themselves well in terms of reliability and stability.

Some difficulties often arise when replacing or choosing an analog for such PWM regulators due to the use of code markings in the designation of the type of microcircuits. The situation is complicated by a large number of component manufacturers who do not always provide documentation to the mass access, just as not all manufacturers of finished devices supply repair service centers with diagrams, so repairmen often have to study real circuit solutions by installed components and wiring connections directly on the board.

In practice, PWM microcircuits and the marking code EAxxx and Eaxxx are often found. Official documentation for them was not found in the public domain, but discussions on the forums and pieces of pictures from PDF from System General, which publishes them as SG6848T and SG6848T2, have survived. The drawing is here placed left .


 

For the attention of the masters, here below are PDF datasheet tables compiled from information available on the Internet and PDF documents for the selection of analogues types when replacing the most common six-legged planar PWM with pinout pins: pin1 - GND, pin2 - FB (COMP), pin4 - Sense, pin5 - Vcc, pin6 - OUT ...
Their main difference is the application and purpose of pin 3. 

 

NamePart NumberFabricantMarking
SG6849SG684965TZFairchild / ON SemiBBxx
SG6849SG6849-65T, SG6849-65TZSystem GeneralMBxx EBxx
SGP400SGP400TZ System General AAKxx

 

 PWM controllers (PWM) with a 95-100 kOhm resistor on pin 3.

When applying the PWM listed below, the frequency should be set with the RT (RI) resistor from pin 3 to ground. Usually its nominal value is chosen 95-100 kOhm for a frequency of 65-100 KHz. For more details, see the here below attached documentation. PDF files are packed in RAR.

 

NamePart NumberFabricantMarking
AP3103AAP3103AKTR-G1Diodes IncorporatedGHL
AP8263AP8263E6R, A8263E6VRAiT SemiconductorS1xx
AT3263AT3263S6ATC Technology3263
CR6848CR6848SChip-Rail848H16
CR6850CR6850SChip-Rail850xx
CR6851CR6851SChip-Rail851xx
FAN6602RFAN6602RM6XFairchild / ON SemiACCxx
FS6830FS6830FirstSemi
GR8830GR8830CGGrenergy30xx
GR8836GR8836C, GR8836CGGrenergy36xx
H6849H6849NFHI-SINCERITY
H6850H6850NFHI-SINCERITY
HT2263HT2263MPHOT-CHIP63xxx
KP201
Kiwi Instruments
LD5530LD5530GL LD5530RLeadtrandxxt30 xxt30R
LD7531LD7531GL, LD7531PLLeadtrendxxP31
LD7531ALD7531AGLLeadtrendxxP31A
LD7535/ALD7535BL, LD7535GL, LD7535ABL, LD7535AGLLeadtrendxxP35-xxx35A
LD7550LD7550BL, LD7550ILLeadtrendxxP50
LD7550BLD7550BBL, LD7550BILLeadtrend xxP50B
LD7551LD7551BL/ILLeadtrendxxP51
LD7551CLD7551CGLLeadtrendxxP51C
NX1049XN1049TPXian-Innuovo49xxx
OB2262OB2262MPOn-Bright-Electronics62xx
OB2263OB2263MPOn-Bright-Electronics63xx
PT4201PT4201E23FPowtech4201
R7731R7731GE/PERichtek0Q=
R7731AR7731AGERichtekIDP=xx
SD4870SD4870TRSilan Microelectronics4870
SF1530SF1530LGTSiFirst30xxx
SG5701SG5701TZSystem GeneralAAExx
SG6848SG6848T, SG6848T1, SG6848TZ1, SG6848T2Fairchild / ON SemiAAHxx EAxxx
SG6858SG6858TZFairchild / ON SemiAAIxx
SG6859ASG6859ATZ, SG6859ATYFairchild / ON SemiAAJFxx
SG6859SG6859TZFairchild / ON SemiAAJMxx
SG6860SG6860TYFairchildAAQxx
SP6850SP6850S26RGSporton Lab850xx
SP6853SP6853S26RGB, SP6853S26RGSporton Lab853xx
SW2263SW2263MPSamWin
UC3863/GUC3863G-AG6-RUnisonic Technologies CoU863 U863G
XN1049XN1049, XN1049TPInnuovo Microelectronics49 xxx

 

 PWM controllers that use pin 3 differently.

When using the following PWM (PWM controllers), you should pay attention to pin 3, which can be used to organize protection - thermal or from overvoltage of the input voltage.
The frequency can be fixed at 65kHz, or set by the value of the capacitor at pin 3.
When replacing any microcircuits with analogs, carefully study the documentation. PDF files are packed in a RAR archive.

 

NamePart NumberFabricantMarking
AP3105/V/L/RAP3105KTR-G1, AP3105VKTR-G1, AP3105LKTR-G1, AP3105RKTR-G1Diodes IncorporatedGHN GHO GHP GHQ
AP3105NA/NV/NL/NRAP3105NAKTR-G1, AP3105NVKTR-G1, AP3105NLKTR-G1, AP3105NRKTR-G1Diodes IncorporatedGKN GKO GKP GKQ
AP3125A/V/L/RAP3125AKTR-G1, AP3125VKTR-G1, AP3125LKTR-G1, AP3125RKTR-G1Diodes IncorporatedGLS GLU GNB GNC
AP3125BAP3125BKTR-G1Diodes IncorporatedGLV
AP3125HA/HBAP3125HAKTR-G1, AP3125HBKTR-G1Diodes IncorporatedGNP GNQ
AP31261AP31261KTR-G1Diodes IncorporatedGPE
AP3127/HAP3127KTR-G1, AP3127HKTR-G1Diodes IncorporatedGPH GSH
AP3301AP3301K6TR-G1Diodes IncorporatedGTC
FAN6862FAN6862TYFairchild / ON SemiABDxx
FAN6863FAN6863TY, FAN6863LTY, FAN6863RTYFairchild / ON SemiABRxx
HT2273HT2273TPHOT-CHIP73xxx
LD7510/JLD7510GL, LD7510JGLLeadtrendxxP10 xxP10J
LD7530/ALD7530PL, LD7530GL, LD7530APL, LD7530AGLLeadtrendxxP30 xxxP30A
LD7532LD7532GLLeadtrendxxP32
LD7532ALD7532AGLLeadtrendxxP32A
LD7532HLD7532HGLLeadtrendxxP32H
LD7533LD7533GLLeadtrendxxP33
LD7536LD7536GLLeadtrendxxP36
LD7536RLD7536RGLLeadtrendxxP36R
LD7537RLD7537RGLLeadtrendxxP37R
LD7539C GLLD7539C GLLeadtrendxxP39C
ME8204ME8204M6GMicrOneME8204xx
NCP1250NCP1250ASN65T1G, NCP1250BSN65T1G, NCP1250ASN100T1G, NCP1250BSN100T1GON Semiconductor25xxxx
NCP1251NCP1251ASN65T1G, NCP1251BSN65T1G, NCP1251ASN100T1G, NCP1251BSN100T1GON Semiconductor5xxxxx
OB2273OB2273MPOn-Bright-Electronics73xx
R7735R7735AGE, R7735HGE, R7735GGE, R7735RGE, R7735LGERichtek
UC3873/GUC3873-AG6-R, UC3873G-AG6-RUnisonic TechnologiesU873 U873G
 



The main features of the device TELEFUNKEN TF-LED32S30T2:

A CX315DLEDM LE-32Z2 matrix (LED panel) is installed.
To power the LED backlight is used converter, combined with the main board CV512H-U42, controlled by a PWM controller BIT3267. The ME15N10 TO-252 type switches are used as power elements of LED-driver.
The power module is combined with MainBoard and is designed as reverse-going converter of AC/DC voltage with PWM SOT23-6 chips and TO-252 type power switches.
MainBoard - the main board (motherboard) is a CV512H-U42 module, using SPI Flash: W25Q64, Audio: RDA3118E28 (TPA3110D) and other microcircuits.
The CDT-9NT372-RD60 tuner provides TV program reception and channel tuning.

TELEFUNKEN TF-LED32S30T2 TV with CX315DLEDM LCD screen measuring 31.5" (80 cm) diagonally in 16:9 aspect ratio. The screen luminance of 250 cd/m² is provided by an LED backlight. Contrast, as the ratio of maximum brightness to minimum brightness, is 2400:1. The LED panel of this TV features Edge LED end illumination.
CX315DLEDM matrix and MainBoard CV512H-U42 software realize HD picture quality at 1366x768 pixels resolution in 720p (HD Ready) graphic decomposition standard. Input high frequency or video signal can be processed in PAL, SECAM, NTSC analog systems. Graphical processing and digital signal formation is performed in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats: MP3, WMA, MPEG4, Xvid, DivX, MKV, JPEG.
The speaker system has 6W (2x3W) sound power provided by two speakers. NICAM STEREO audio processing system is used.
External interface (connection with other devices) is supported by standard inputs and outputs: antenna input (RF), AV, audio x2, component, VGA, HDMI, USB. There is a headphone output. To connect a computer or laptop to this TV model uses a VGA (D-Sub 15) connector on the TV body, this interface supports resolutions: 640x480, 800x600, 1024x768, 1360x768. The digital tuner is able to receive DVB-T, DVB-T2, DVB-C TV channels.

It uses power supply as a part of MainBoard.

Dimensions: with stand 729x469x168 mm, without stand 729x429x76 mm.

TV weight: 3.5 kg.

Warning. The CX315DLEDM is an expensive and fragile part of your TELEFUNKEN TF-LED32S30T2 LED TV.
Do not apply any impact to the glass and do not exert any pressure on the screen surface to avoid damaging the LED panel!
Also it is not safe to get liquid on the screen. Sometimes one drop is enough if it drips down the glass onto the cables and the TV becomes unrepairable.