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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All posts are presented here for informative, historical and educative purposes as applicable within fair use. NOTHING HERE IS FOR SALE !

Friday, 22 January 2021

REPAIRING / SERVICING TV AKAI LES-32A64M


 Technical description and composition of the TV AKAI LES-32A64M, type of panel and modules used. Module composition.

AKAI LED.
Model: LES-32A64M

Chassis/Version: TP.MS338E.PB803

Panel: LSC320AN09 D00

LED driver (backlight): integrated into MainBoard

PWM LED driver: PWM SOT23-6

Power Supply (PSU): integrated into MainBoard

PWM Power: OB2273 (PWM SOT23-6)

MOSFET Power: TK5P65W 650V5.2A TO-252

MainBoard: TP.MS338E.PB803

IC MainBoard: CPU: MSB102KT, eMMC: THGBMDG5D1LBAIL, SPI Flash: 25L4006E

CPU: CDT-9NT372

Specifications LES-32A64M
AKAI LES-32A64M
General recommendations for LCD LED TV repair
Possible defects

- AKAI LES-32A64M does not turn on and does not show any signs of working at all. Does not flash the lights and does not respond to the control buttons.

First of all in such cases you should check the operability of the common switching power supply (PPS) - AC/DC mains voltage converter. All power supply elements in this TV model are located on the MainBoard TP.MS338E.PB803. It is necessary to measure the output voltages in its secondary circuits, and in case of their full absence you should check the serviceability of the power switches (TK5P65W 650V5.2A TO-252) and the rectifier diodes on the possible breakdown (short circuit).
If the semiconductors in the secondary circuits breakdown, the inverter can usually be short-circuited, and the mains fuse is often blown when the power elements in the primary circuit are shorted.
Mos-Fet switches used in switching power supplies usually fail due to the failure of other elements that can take it out of key mode, or cause it to exceed the maximum current or voltage. These may be the circuits feeding the PWM controller, the damping or frequency-retaining circuits, or the negative feedback elements in the stabilization circuit. PWM controllers OB2273 (PWM SOT23-6), if there are no external damages and short circuits between pins, are checked by replacing with known good ones.

- No picture, sound is present and all other TV functions work. When switching on, the picture can sometimes appear for a second.

Often in such cases there is no backlighting of the LED panel. Usually the cause of the fault is in the breakage of the LEDs, or in the connectors of the LED strips, but sometimes the LED-driver is also faulty.
It is better to use a power supply with a maximum voltage of 200V to check if the LEDs are working. It is not recommended to use any voltage sources for this purpose. You can check each LED individually with a simple Chinese multimeter (9 volt) in P-N junction test mode. If you connect the red probe of the multimeter to the anode of the LED and the black to its cathode, then the 3 volt LED will light up slightly and in the opposite direction you will find the faulty junction of the stabilizer. The functionality of the PN junction is indirectly an indication of the functionality of the LED.

- The TV set doesn't turn on, the LED indicates standby or operation mode, or blinks.

Repair or diagnostic of the TP.MS338E.PB803 motherboard should begin with checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (firmware). Complex repair of MB (SSB) is possible only in the conditions of the service center with the necessary equipment. Check or replacement of CPU: MSB102KT, eMMC: THGBMDG5D1LBAIL, SPI Flash: 25L4006E requires the necessary training and professional skills to repair modules at the component level. Problems associated with the use of BGA soldering technology can sometimes be diagnosed by the heating method.

If there is no TV channel reception, but the TV set is working properly from external devices, first of all you should check the CDT-9NT372 tuner supply voltage and update the software. It is necessary to check the I2C bus communication pulses with an oscilloscope.

If the AKAI LES-32A64M has no picture but has sound, often the HV320WHB-N5K display backlight simply does not work. Moreover, in LED TVs the LEDs inside the panel usually 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 HV320WHB-N5K LCD panel, a process that requires a master of experience and skill. 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 MainBoard TP.MS338E.PB803 is also defective, so software defects are also possible.
Then first it is necessary to check the panel power supply voltage, the 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, you need to trace by oscilloscope the LVDS signals from MainBoard TP.MS338E.PB803, as well as synchronizing signals to driver stubs.

Filled or badly washed LED TV screens can be repaired in about half of the cases, usually, if there is no significant damage in the cables and panel bars.

Remember! Attempts to repair TV AKAI LES-32A64M by yourself, in the absence of the necessary skills and experience, is categorically not recommended and is fraught with negative consequences, up to the complete unrepairable device!

To reduce the backlight current from 290 mA to 230 mA you can remove the 1,6 Ohm resistor in the current sensor (E8303 assembly) on the TP.MS338E.PB803 board.
More on MainBoard repair

The appearance of the MainBoard TP.MS338E.PB803 is shown in the figure below:




TP.MS338E.PB803

The main features of the device AKAI LES-32A64M:

A matrix (LED panel) LSC320AN09 D00 is installed.
The backlight LEDs are powered by a converter combined with the main board TP.MS338E.PB803, controlled by a PWM SOT23-6 controller.
The power supply module is integrated into the MainBoard and follows the reverse-going AC/DC converter circuit using OB2273 (PWM SOT23-6) chips and TK5P65W 650V5.2A TO-252 type power switches.

MainBoard - the main board (motherboard) is a TP.MS338E.PB803 module, using CPU: MSB102KT, eMMC: THGBMDG5D1LBAIL, SPI Flash: 25L4006E and others.
The CDT-9NT372 tuner provides television program reception and channel tuning.

More technical information about the panel:
Brand : SAMSUNG
Model : LSC320AN09
Type : a-Si TFT-LCD, CELL
Diagonal size : 31.5 inch
Resolution : 1366x768, WXGA
Display Mode : SVA, Normally Black, Transmissive
Active Area : 697.685x392.256 mm
Surface : Antiglare (Haze 2%), Hard coating (2H)
Glass Depth : 0.50+0.50 mm
Transmissivity : 6.9 % (with Polarizer)
Contrast Ratio : 4000:1
Display Colors : 16.7M (8-bit), sRGB 68%
Response Time : 20 (G to G)
Frequency : 60Hz
Signal Interface : LVDS (1 ch, 8-bit), 30 pins
Voltage : 12.0V


 

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

 

 

 

 

AKAI LES-32A64M LCD TV set with the HV320WHB-N5K, which measures 32" (81 cm) diagonally in 16:9 aspect ratio. The model's display technology uses LED backlighting.
LCD panel HV320WHB-N5K and software MainBoard TP.MS338E.PB803 provide HD image quality at 1366x768 pixels in 720p (HD Ready).
The TV model LES-32A64M has built-in SMART software and pre-installed the Android operating system. Connection to the network can be made via Wi-Fi wireless connection. Supported media formats: MP3, MPEG4, MKV, JPEG.
Two speakers provide sound power of 12 W (2x6 W). NICAM STEREO audio processing system is used.
External interface (connection to other devices) is supported by standard inputs and outputs: antenna input (RF), AV, component, VGA, HDMI x3, USB, Ethernet (RJ-45), Wi-Fi. There is a headphone output. The digital tuner is capable of receiving DVB-T, DVB-T2, DVB-C television channels.

The TV set uses the power supply as part of the MainBoard.

Overall dimensions: with stand 730x465x230 mm, without stand 730x435x85 mm.

TV weight: with stand 4.14 kg, without stand 4.03 kg.

Warning. The HV320WHB-N5K LED TV AKAI LES-32A64M panel is an expensive and unreliable component.
Avoid any kind of impact on the glass and 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.