Troubleshooting LG TVs
LG CF21D70. When you turn on the TV, after 2-3 seconds it goes into standby mode. The reason for the breakdown of the diode 2N4148 (150V) according to the D408 circuit. Already 3 cases in 3 months.
GOLDSTAR CKT-4905 The TV does not turn on. The output is instead of 115 volts 40. over, the voltage on the diode is normal, and after relay 40, the power supply works without additional sounds of overload. The 115 volt diode is very hot. When checking the secondary circuits, no suspicious details are detected. The capacitor C8075 160V \ 33Mkf turned out to be faulty. Checking the capacitance on the device showed that instead of 33 Mkf, only 0.23 Mkf, the leakage was 50 ohms. The defect is very common. I replaced the punctured TDKS in LG TV: 154-375F, after which I observe a strange effect: service information (program number, menu lines) twitch vertically 2-3 cm, the main image is normal if you reduce the voltage SCREEN by TDKS twitching stops, also affects the brightness of the plot. It turned out that the secondary voltage from the TDKS to the power supply is overstated. 29v instead of 24v. I put sequentially 3 diodes in this circuit and that’s it.
TV LG CF-20D30 when turned on, the network button blinks an LED on the front panel once and nothing more. BP did not start, there are no secondary output voltages. The electrolyte in the STRS5707 strapping (standing between the radiator plates of the STRS-ki, C = 4.7μf50V) was found guilty, which lost capacitance up to 1 μf.
Gold Star (LG) 21D16. The guys overdid something in this model with stereo sound on an additional board and TDA2009A. In a number of boxes, after six months or a year of work, a problem appears in the form of a hoarse (farting) and weak sound. The most optimal solution to the problem, without replacing the microcircuit, was a hanging of resistors 2. 3 MΩ between the input of the first and second channel TDA and 12V.
Goldstar CB-28C22X. Narrow horizontal strip. Penetrated 2-Zener diode 24V, charred R304. After replacing the zener diodes, the band remained, the R304 heats up. Replaced out. K. frame. develop., TDA8350Q-resistor stopped warming, but the strip is still. (The desired scheme is at hand, as always). After analyzing the circuit, I found that 2 power supply comes to the ms personnel: 4 and 8 legs. On 4 conclusions D702 is broken, FR702 break. After the replacement, the TV worked. (On the Internet, a dock on the TDA8350Q can be found on the pro-electronics website.)
TV Goldstar CF-21E60B. External symptom of malfunction. h / c a few minutes after turning on. lack of image (dark screen) and sound in the presence of a raster, there is no reaction to commands from the remote control (it is controlled from the TV panel), and in the future. failure of synchronization and spontaneous entry into standby mode, and after a while the functions are restored, and everything repeats. Malfunction. in the processor LG8534-13A, part of the circuit of it. analog adjustments, inclusion. shutdown, remote control decoder during heating fail. Treatment. in secret ¦125, without soldering, applying a layer of CBT and applying a copper plate to the size of the case on top, roasted it with a 65-Watt solder, until the solder on the plate stopped solidifying (8-15 seconds). The second successful recovery.
LG CF-21K49 based on the MC994A chassis. The symptom does not turn on or has a narrow vertical strip on the screen. Most likely, a capacitor C411 334 / 200V should be replaced.
LG CF-20D30 (Chassis: MC64B). There is no reception on the upper meter subband. The malfunction came to light rather unexpectedly. The main one (by which there was a call) was: the network power button (white, expensive 150 rubles) deteriorated. After replacing the circuit breaker, it turned out that there is no voltage to turn on the NV sub-band (instead of 12V, only about 5V). Switching voltages are supplied through transistors, a quick check of which showed that everything is OK. Everything was rounded off, as it were, on the tuner (the usual octopus). But I have never encountered something of such a defect. Doubts were true. After soldering the little things around the output of the NV tuner, it turned out that the Q181 2SA1266 transistor (p-n-p 50V 0.15A) on Ohms rings like normal, and on kOhms it has R (b-e) arr. = 150kOhm. He then planted 12V at the output of the tuner.
TV LG-CF21D79, oversaturated color image b / w no, as if there is no luminance signal. Replacing the TB1238BN processor yielded nothing. The SECAM TA1275AZ chip turned out to be faulty.
TV LG20 on the MS-84A chassis. The defect may not be widespread (met once), but it seemed interesting to me. Slowly responding to commands, poorly configured and does not remember settings. The service turned out to be all the settings on zeros, but when entering the proper initialization modes and exiting the service, everything repeated. Replacing the memory gave nothing. It turned out that two of the eight resistances in the ceramic assembly instead of 4.7kOhm showed
Problem with LG chassis MC-019A. The TV does not exit standby mode if you measure the power of the line. About 70 volts. First of all, see the C820 220 MF 160 B, most often one of the capacitance leads is torn off, the terminals are formed at a very sharp angle.
LG CF-21D70 (Chassis: MC-64A). When turned on. goes into standby mode, and then completely goes out. The analysis showed that when the mains voltage is applied, the output voltage V smoothly rises to more than 160 V (norm 125 V), and then the internal protection is triggered and the PSU generation breaks down. Analyzing revealed a defective electrolyte C824 4.7uF 50V (leakage, drying out or increase in internal resistance on the RF), established between 4 pin. optocouplers IC801 and 7 vyv. STRS5707. What pleases. this is a timely internal defense, which did not allow the killer B = 160-180V to clear up.
TV Gold Star CF21E20 chassis MC-41A The sound is gone. Pretty quickly I found that the volume control signal was almost zero, you unsolder the GS8434-16 control output (3pin). it screams to the full, there is no sound in AV mode either, everything seems clear, you need to change the percent. not so rare. But after the replacement, the situation has not changed, flashing the flash drive to a knownly good one also failed. I had to start thinking. I take out the antenna, after 10 minutes the TV turns off, well, that’s right. I leave it with a signal from the ether — it switches off after the same 10 minutes — it is clear that there is no SOS signal (it is indicated here as processor ID-17pin) —it is constantly high. Unfortunately, the stereotype of thinking worked here. I submit it low to this input, but the situation does not change, and there is no sound either from the input mode. In many television processors, the SOS signal is integrated and evaluated by level, respectively, and it is easy to track it. when the station signal disappears, the level changes dramatically. Here the signal is pulsed. SSC pulses are used. Transistor Q06- ID Signal Conditioner “drip” transition K-B, there were no pulses at the input ID. On SAMSUNG TVs in the event of a failure “sweet couple” and the R2M breakage of protection pierced the TDKS- in the upper part, near the output of the high-voltage wire, a mother-of-caulk about 5 mm formed and a spark sparked from it into the core. Here, advice on TDKS restoration helped a lot — I drill a couple of mm deep into the crack with a large drill and fill it with a white sealant, after 3 hours you can turn it on. Thus, 2 transformers per week.
On the tv LG-21D70X when you turn on, switch programs, information about the settings is not saved. After pressing the network button, the TV switches to LINESVC mode, from which it switches to normal mode after pressing the TV / AV remote control button. After replacing the 24С02 memory and turning it on, the TV switched back to LINESVC mode, then after pressing the TV / AV button on the remote control, the TV switched to normal mode with restoring the settings saving functions. No additional steps to “firmware” no memory chips were needed.
GoldStar and LG TVs until 2000. Problems with the tuner, does not remember the settings, etc. It looks like a tuner out of order. Solder earth contacts in the tuner.
Tv Goldstar CF20A80Y. When turned on, you can hear the sweep, but there is no sound and raster. The malfunction is in m / s D402 (7809) manufactured by KIA. She stands with D401 (7812) on one heat sink, not far from the TDKS.
Gold Star CF-29C44 When you turn on the TV goes into protection. Replace the position number IC7P on the PIP BANK 78L08. Almost all the malfunctions in these models are associated with this product.
GoldStar CF-21D60B. No sound. I got the 2nd TV with such damage. The sound adjustment output on the 3rd leg of the LG8434-03C processor is faulty. We have a processor
800 rub. If the client is satisfied, the sound can be set to adjust the contrast of this processor. Contrast set optimal at your discretion. The only inconvenience. sound adjustment through the menu.
LG CF-20D60. It does not turn on, when measuring in the power supply, it starts up. A replacement of 4.7mFx50V capacitance is needed (located in the 5707 heatsink alignment).
LG CF-21D70 Spontaneous transition to standby mode. On different channels in different ways, on some after 5 minutes on others after 10 minutes. Try to replace the electrolyte of position C408 with a nominal value of 160V1mF, it has dried up to 0 and in addition it was also in leakage.
LG CT-29K37E. When you turn on the relaxation of the power supply, it enters the working mode after 5-6 on-off attempts. It is necessary to replace C808 (100.0x35V) in the power supply, which is assembled on the STR-F6656 chip.
LG CF21D33. does not turn on. 185v = short to the ground. change TDA6107Q (by the way, there was a recently defective batch of these ic in Promelectronics with the number 3 in the lower right corner)
-penetrated quietly pierced D5072. change and get a heartbreaking whistle. (what were they fighting for?). It turned out that Korean saboteurs smeared a new OS from within “superglue”. But nothing, we are not proud people. remove the OS, wash the short circuit with the purest Russian alcohol, we spread the turns, we put insulating tape. and everything is in place.
GoldStar SF-14A90B a few seconds after turning on, the screen turned bright white. The KIA7805 stabilizer (5 V), which was powered by the processor, turned out to be faulty; during these several seconds it raised the voltage at its output to 7 volts.
Supra CTV1485 MC-41A chassis, aka Goldstar GF-14/20 / 21A80 MC-41A / B. There is no blue color in SECAM, everything is OK in PAL. In SECAM, the contour of the blue B-Y core L504 does not respond to rotation. Do not rush to change the TA8750AN chip, swap the L504 and L502 circuits connected through the capacitors to the pins 35 and 29 of the TA8750AN. In my case, after rearranging the circuits in places, everything worked, obviously, the soldering of the legs (inside) of the circuit affected, after which a small adjustment of the circuits is required.
LG CF-21F89 Chassis MC994A Symptom. turns on for a few seconds then goes to st-by. During turn-on, the line transistor manages to heat up. Locked lowercase coil in the OS.
LG CF20F30. The fuse is on. The diode bridge is broken and the IC802 STR5707 chip. The bridge was soldered from the KD105’s, bit off 1 and 3 conclusions in the microcircuit, turned on, there are start pulses on the 4 leg. I suspended the KT872A transistor on the wires (k-1n, b-3n, e-2n), turned it on. Trp put on a suitable radiator.
LG CF-21D70 chassis MC64A. Spontaneously randomly goes into “the duty room”. Regardless of operating time, heating or cooling. Replacing processors and memory did not produce results. As a result of long searches, the defect was nevertheless revealed. Shrunken С408 1мкфХ160в in the Q401 chain (the tip of the stringer). B.P. does not start in these TVs drying S824 4.7mkfH50v in the optocoupler circuit.
GOLDSTAR is assembled on TDA3562A. Dark screen. Reason C.10mF / 250V, 180V filter
GOLDSTAR CKT9905. The faint image, 112V is normal, and the supply voltage of 180V amplifiers is overstated to 270V. Defective C806 (47mF / 160V)
GOLDSTAR CKT9582. White raster with reverse beam. leakage of the transistor Q906 (BF421).
LG CF-20K51KE Breakdown of the lowercase transistor Q402 D5702 on the body, with burnout. After replacement. a new one flew out after a second. Replaced Q402 On BU2520DX, they are more reliable. A thorough check of the binding. brought no result. Disconnected one output of the lowercase coils of the OS and briefly turned on the TV. The screen lit up with a strip. Turned on briefly with the OS. The screen lit up with a compressed screen. The transistor remained intact. Replaced the OS. The result is positive. In a broken OS. found no defects.
GOLDSTAR 21E60. It does not turn on. Broken line transistor, TDKS and interturn circuit in the deflecting system.
LG CF-14G20R. Weak sensitivity. The image shows interference and noise. Guilty of this disgrace was the IF filter of the K6265K radio channel.
GOLDSTAR 21E40. No high voltage. BP works, there is sound. The amplitude of the horizontal triggering pulses is small based on the SR output transistor. On the 37th leg of the processor, a voltage of 0.4 V. Reduced R524 resistor from 3.9 kΩ to 2.4 kΩ. The voltage increased to 0.57 V and its amplitude was enough to open the transistor.
ELEKTA CTR-1495EMK, GOLDSTAR CKT-4442B, CKT-9322B. Chassis PC-05X2. (There is no image (it may dimly glimpse), the screen is gray !, there is sound. One of the reasons for such a defect is the failure of the switch, the microcircuit (GL3820, aka TEA2014A) is located on the input board.
ELEKTA CTR-1495EMK, GOLDSTAR CKT-4442B, CKT-9322B. Chassis PC-05X2. Defect. missing color image in the SECAM system. Pretty common reason. tuning capacitor SVC1 (standing next to the quartz resonator) in the SECAM-PAL transcoder circuit.
ELEKTA CTR-1495EMK, GOLDSTAR CKT-4442B, CKT-9322B. Chassis PC-05X2. The TV does not tune in or the setting fails. Perhaps, just soldering and soldering the tuner is enough. At least a defect has occurred.
ELEKTA CTR-1495EMK, GOLDSTAR CKT-4442B, CKT-9322B. Chassis PC-05X2. The TV does not turn on, there is no indication. The transformer of the standby power supply often fails. TP-8-3, or similar, is suitable for powering a 12-volt source. However, there was a case when standby power was turned out to be. ring break of Krenki IC2 (7805) 🙂
ELEKTA CTR-1495EMK, GOLDSTAR CKT-4442B, CKT-9322B. Chassis PC-05X2. No image, the screen is dark green, visible “Suckers”, Is there sound. Cause. drying of the air conditioner in the power supply circuit of the amplifiers (the voltage dropped to. 119V, instead of 180-190 set! The screen may be completely dark (the power supply of the amplifiers in that case was about 160 volts).
ELEKTA CTR-1495EMK, GOLDSTAR CKT-4442B, CKT-9322B. Chassis PC-05X2. The screen is bright white (or gray), brightness, etc. is practically impossible to adjust, the image only skips when you turn on the TV. Most likely this defect. feature of color blocks with ABB scheme. The cause of the malfunction is most often the processor or transistor A1015 on the kinescope board.
GOLDSTAR CF-20E20B When you turn on the TV, there is no raster and sound, there is a high voltage. Fault: stabilizer IC402 (KIA7809)
LG CF-20F30 chassis MS-64A independently turns off in standby mode from 10 minutes to an hour. The whole board is literally “plowed on elephants and camels”, did not touch only the percent management due to its high cost. The reason for turning off the LG8634-16C processor on the 20th output, through the ABNORMAL protection bus, is the loss of the capacitance of the C408 1mkf160v capacitor in the TMS primary power circuit.
Goldstar LG CF-14/20 / 21A80V Does not leave standby mode. When a command is given to turn on, the voltage tries to increase and immediately drops to the standby mode. Replace SE120N. Sometimes the PSU does not start. The starter circuits should be soldered.
LG CF-21F3. Immediately after switching on, it goes into standby mode. No vsync on the processor. Fault-open R15 4.7k
LG, CF-21F39, 2 years. When transferring from standby to working mode, a burning smell appears and the TV goes back to standby. Open the lid, turn it on. There is a smoke on the left side of the OS. We remove the deflecting one. On the inside, a breakdown is detected between adjacent windings. At the junction separated by a plastic hem OS shell. The insulation is burnt on 3-4 wires on each side. It is necessary to carefully dilute, remove “coals”, lay wires in cambric and fill with sealant. The interesting thing is that after 1.5 months the client complains that again the same thing. The smell appeared and turned off by itself. I take off the OS and find the same breakdown only now on the right. But this is a topic for reflection. As written on the cover of the TV: made in Ukraine from components of the company LG. On the deflector we read: Planzhuan OPC 29-90-54. Made in China. But there is one more point. Rubber wedges, which are placed under the OS, (which are usually 3 pcs. And stand at an angle of 120 degrees) here are 4 pcs. Two vertically and two horizontally. exactly under the place of breakdown. It seems that the rubber is not conductive, but heat may be poorly removed, etc. Or the Chinese drive the marriage. Life will show.
LG CF-21D33E, chassis MC-84A similar breakdown deflecting system Pianzhuan QPC 29-90-54. Assembled. When trying to replace the OS, large dilutions from the top and from the bottom. Breakdown occurs in two places where the turns from the two coils are closest, located on the horizontal axis. At these points, the turns are additionally fixed with a brown compound. Through it, the circuit breaks. After uninstall “coal” and the compound on the opposite side, the wiring of the turns, and the pouring of hot glue, the OS earned. The information got up at its best.
I confirm this defect. Two TVs in a week. OCA Pianzhuan QPC 29-90-54. The TV is assembled. We could not pick up another OS. Correction is not displayed. Restored the old OSKI!
GoldStar CF-14A74Y chassis MC41A after a thunderstorm, the STR-S6707 and the TPL721 optocoupler flew out. After replacement and when checking b / p. on an external load of 60W, it worked fine. When you turn on the TV, the 112V channel is set to 85 and 90V, i.e. with a frequency of approximately 3-6 seconds, voltage jumps from 85 to 90 and vice versa occur. At 85V, the screen is squeezed horizontally and a white screen, and at 90V the TV works fine, but there is a buzz of change in the speakers and the horizontal transistor is heating. Faulty, the SE110 chip turned out to be (it turned out that the reason was after connecting an external load of 150W to the b / p).
GoldStar CF-21E60B Image distortion, lack of luminance signal, color violation. Replacing the TA8750 and the TA8690 processor, soldering the tuner did not give anything. The voltage of 12V and 9V is normal. Faulty IC201 LA7222. input switch
LG (I don’t remember the model) with a 24С02 memory microcircuit. If, after switching on, the volume is controlled by the buttons on the front panel, then it is regulated as follows: 0-50-100-mute, if you turn it off in standby mode and turn it on. fills with white, protection works. Replacing the memory chip fixed all the problems.
Defect.no frame scan in devices: LG CF-20E60K chassis MS-64A. Open resistor R311 2.2 ohms.
Goldstar CF-21D10B No image or sound, no noise, the screen is dark. Almost like in secrets No. 487 and No. 949, but. service info is displayed (menus, knobs, channel number, etc.) Fault: in this case, IC401 (KIA 7812) is located on the same heat sink as D402 (7809), not far from the horizontal transformer.
LG CF-20K50E chassis MC-84A. It is on duty and does not turn on either from the remote control or from the TV panel. It turned out one 4.7k resistance in the ceramic assembly near the control processor in the open. I hung a similar resistor on the other side of the board: the box worked, but the raster is compressed vertically and shifted to the left. I did not go into the service, I changed the memory, the raster became normal.
GoldStar CF-21D60. The raster is dimly lit, there is no image, there is sound. The amplitude of the V-Syng pulse at pin 2 of the processor is small
1V. The reason is the punctured Zener diode ZD01 (5V1).
Goldstar CK-20A80. No image, sound, OSD, amplifiers are locked. Sometimes she doesn’t even want to get out of duty. Faulty m / s EPROM (24С04). Solder clean and all.
LG CF-20F60. Entered from another workshop with a diagnosis. processor faulty. The device behaved quite original: at first it started to work, after five minutes it hung up and did not want to work for more than a day. After resting for about twelve hours, he began to work again, hung up, and everything was repeated anew. Three resistors in the AR02 assembly turned out to be faulty, two of them were connected to the processor I2C bus pins, and the resistor values did not change upwards, as is most often the case, but down. Instead of the set 4.7 kOhm, it became 2: 3 kOhm. For reliability, I had to replace the entire assembly with ordinary resistors.
GOLDSTAR CF-25C36X. Defect. there is no image and sound, there are weak noises on the screen. Suspicion first fell on TDA9808 (radio channel), but the reason was IC182 KIA7805 (5-volt power supply TDA9808). instead of 5 volts it issued 3.
GOLD STAR CF-29C32J Does not turn on (after a thunderstorm). Punched tr Q301 2SB988Y replacement for 2SB1294. TV did not turn on, there is no primary circuit start. Cliff R811 470k after replacement earned.
LG, chassis MS-64A, PSU on the assembly STR-S5707. The PSU does not start. Leak in C820 220 uF, which is on the 9th leg of the assembly. The capacity showed normal and did not reveal itself when a digital tester rang. The voltage on this leg was 7.2 V (instead of, as it turned out, 7.9 V).
LG modelCF-21K50E. Defect. there is sound, no image, the screen is dark. At autopsy, it turned out that there was a glow, and there were voltages at the cathodes too. With increasing accelerating voltage, a bright narrow horizontal strip appeared. The defective turned out to be a personnel chip LA7830 and a 1-ohm resistor for powering this chip. The chip flew out due to increased voltage from the power supply (145 volts). Cause. dried electrolytes in the harness of the power supply chip (STR-S5707). After replacing the electrolytes, BP began to produce 115 volts.
Goldstar CF-20A80V. The power supply does not start. Before the breakdown, the TV did not start well and turned off on its own. The soldering of the annular crack of TPI output did not help anymore. At 9k STRS6707, the supply voltage = 0. (start circuit). There was a leak in the 9th input of the chip.
GOLD STAR CF-20D60B. There is no color in PAL, although the screen displays: AUTO PAL. At the conclusion of 40 m.s. IC501 TA8690 instead of 4 volts is only 2.6. Reason: broken output 33 (SECAM-ID) ms. IC01 GS8334-16A. It was not required to change the percent. it was enough to disconnect the defective output from the circuit.
GOLD STAR CF-20D60B. There is no color in PAL and the inscription on the screen reads: AUTO SYSTEM SECAM. At the output 40 ms. IC501 TA8690 in PAL voltage 0.78 V. Faulty TA8690.
GOLD STAR CF-20E20B. Another addition to secret 509. SECAM is dominated by red. Malfunction of the capacitor integrated in the L502 E16A (R. Y) circuit. The defective one had to be broken down and replaced with an external one at 100 pF with a slight adjustment of the circuit.
GoldStar CF-21D70R spontaneously enters standby mode at different intervals, circuit protection is triggered “Abnormal”. A defect has been detected. dry capacitor C408 1.0 x 160 V.
LG-CF-20D70K Returning to secret 415. Degradation of the capacitor C824 in the PSU (4.750 in) initially leads to difficulties with turning on the TV, but our people are stubborn. Repeated on-off tv turn on. And in the end it will all end with the breakdown of the power mx STR-S-5707. This malfunction becomes characteristic of LG, along with the triggering of protection due to a malfunction of the 1.0160v capacitor in the preliminary cascade of lines.
GoldStar CUT9322 chassis PC-05X2 (with “flat tube” in the form of a removable glass). Fills with milk, the image is not visible. Replacement TDA3562A. All the same, the effect remained, although a weak image in the negative began to break through. When the 8-pin TDA3562A touches the probe, a normal image appears. Conclusion. the constant falls through the capacitance C514 0.22mF x 50v. Replacement helped, but not for long. The next time you turn it on, the effect is repeated. Enumeration of containers of various quality yielded nothing. New conclusion. TDA3562A microcircuits of the last years of release have changed input impedance at input Y (8 pin). “Planted” This input is a 1.5 mΩ resistor. Everything works great. An additional check of the previously soldered TDA3562A confirmed that it was killed just by input Y. A rare coincidence of 2 simple defects leading to the consequences-pathologies, which some masters call “drummer”.
GOLDSTAR (LG) CF-14E20B chassis MC-41B . Lights up red (DR indicator), does not respond to buttons, B = 43V. Cause. X01 (for some reason stood 3.6MHz). According to the 4 MHz scheme, as not turned out. set 4.43.
GOLDSTAR (PC04A) 1). Replacing C807 2) is not included in the operating mode 2). the chassis of the MC41V is not adjustable; the sound is not configurable; ROM replacement programs. 3). No sound replacement Q06 adjustment L508. 4). There is no setting of the first range setting L508, 507. 5). The frequency of replacing the m-controller is running out. 6). No Y. Signal replacement LA7222. 7). Underestimated voltage replacement ZD811 to 7.5V.
GOLDSTAR CF-21E20B and other MC-41B. With warming, it turns off itself, the DR indicator may blink. You can turn it on only after a while. If you do not first discharge the filter and touch the 5 legs of the T802 (there is an annular crack), you can burn STRS6707. One unit “pulled” just by taking out the board. while he laid it on the table (before that the TV worked. but waited for the self-shutdown.). It is possible to start after replacing the STRS6707 only through a lamp of at least 300W (the weaker ones flash up due to the rapidly growing current consumption in a few seconds).
GOLDSTAR CF-21C22X MC-46A. Blown on. The DR indicator lights up when turned on. goes out. For a moment, high and all other voltages appear (not reaching the norm), and then fall. When TESTING the output stage of the horizontal line lower B = 15V. impulses without distortion, may be slightly underestimated, the current is normal. BP without suspicion. I would have been tormented for a long time. But he hung up another OS and Wonder TV turned on with a narrow chaotic raster. There was a smell of burning. Only a long thorough inspection of almost ALL the details of the SR helped. The culprit was the C401 434n \ 200V. He tried under voltage and lost part of the capacity. It was cracked, but on the board it was imperceptible. I think that testing would not be helped by an underestimated B = 15V, but a gradual increase in B to nominal. But there was no source and measures should be taken to limit the current. so as not to burn the test generator itself.
Goldstar does not configure channels on the TA8690 processor. For those that were configured, the setting went away. The AFT circuit did not work on the TA8690 processor after the replacement of the processor went back to normal
GOLDSTAR CKT9905 Malfunction: after turning on, after 5-10 minutes the TV turns off, and the indicator panel goes out. After analysis, the suspicion fell on the power relay. power off the output stage. When the jumper closed the working contacts of the relay, the TV worked normally. After replacing the relay, the TV started working again.
LG CF-20F89. Chassis MC994A. Fault: does not turn on. Power supply on STRF-6707A (not to be confused with STRS-6707). In principle, no. The chip itself is to blame. But a careful dialer of her findings with an ohmmeter did not reveal any differences from a working one. The board was removed from the TV. After replacing the chip, the PSU started up, but when switching from standby to working mode after five seconds. went to standby again. Not immediately, but guessed to connect a rejecter. It turned out that without it, TV does not go out. This is nothing. On some instances of Funai, without a diver connected, a horizontal transistor was knocked out.
LG CF-21S10E There is no frame splitting, we change the TDA8351 frame chip. We get an image compressed from the bottom up to half the screen, we change the TDA 8842 processor, the image is normal, but don’t have to rejoice, everything can happen again, and the TDKS 6174Z-8005A is to blame for this disgrace. Sometimes it breaks through.
LG CF14E40 no settings replace. TDA8362-5
Goldstar on TDA4601 When you turn on the TV, the Q801 BU508D crashes immediately. On TV on the bulbs there is no start, but generation in TPI is audible. The power supply for 9 n TDA4601 is underestimated, on the basis of the BU 508 there are irregular ripples with interruptions (that is, rectangular pulses of a normal form of output.) Replace C 801 10X16V. In the event of failure of the Exit TP, it is MANDATORY to check R 270 Kom (with the number of TPs through the TPI winding to the 4-leg 4601). There is no start, but sometimes it can turn on, check 12V (power supply 4601, 9-leg. Must be 12V for start)
Goldstar on TDA4601 periodically outputs a line transistor (42-cm kinescope), power supply B is equal to 140v and is adjustable upwards. Check the soldering resistance R805 coming from the 3-pin TDA4601 on the regulator B (should be from 6k2 to 12k) in this unit increased to 16k.
Goldstar CBS-6081 A very bright glow of the raster, it is not possible to reduce the brightness control and Screen on the TDKS, by replacing it, check the BF421 on the picture tube board.
Goldstar CF-20D60B, chassis MC-41B When the PSU is turned on, the STR-S6707 does not start. Synchronously with the power supply, the LED on the front of the TV flashes. Faulty Zener diode ZD811 6.8v in the base KTD2092.
LG. CF-20D73 (chassis MC-84A). The device after a thunderstorm. When the TV was brought to me, the processor reset chip (KA7542) was soldered there, the stabilizer 7805, the SE115 was soldered to the PSU, the jumper for the power supply of the amplifier (TDA6107Q) was soldered, and the line transistor (D5702) was soldered. I loaded the BP light bulb. works (put 115 at the output). By the way, when you turn on another bulb instead of a fuse, it starts, then a lamp that instead of a fuse glows smoothly and the PSU is cut off. And without it, everything is OK. I sealed the power jumper on the amplifier, put the KREN-ku, the lower case transistor for testing (BU208), cut the horizontal scan through the lamp. caught fire. KZ in the lowercase. Disconnected the amplifier. KZ no. Turned out to be a breakdown on the power m / s amplifier (6 ohms). The processor (LG-8838-07D CXP86441) also turned out to be dead (breakdown on the 18 Reset foot). The LED and the diode standing in series with the LED also burned out. The LED set a suitable diode in size. KD521. Replaced the processor, amplifier, set the line transistor D5702, a reset chip. The TV started, but instead of the image. white screen (with a pinkish tint) screen with reverse lines. Indication on the screen is present. Replaced the processor (TDA8842). An image appeared, but flooded with white, and with Lochs. Reduced accelerator. the image is normal (low frequency). Does not remember settings. memory unspecified (24C04). No reception of channels. Tuner defective (TV8PSB02D 911A290E). Inside the tuner I found two burned tracks. Sealed jumpers. There was a bad reception only on the 1st range. Replaced the tuner with the 6700VPF016A. The remote control does not work. IR receiver defective. IR receiver and reset chip set from a VCR. work great. He eliminated a small pink spot on a blue background in the center of the screen by twisting the magnets on the neck of the picture tube. And lightning hit the antenna. burned out track of mass from the tuner to the arrester with network wires, and another track near the tuner. In the service, I adjusted the AGC, geometry, I did not touch the white balance. Login to the service. simultaneously press the OK button on the TV and on the remote control. To switch the menu in the service, you must press the yellow button on the remote control. Since there was no such remote control at home, I used the Chinese universal remote control.
LG CF-21D70 (Chassis MS-64A). in the bowl. mode turns on. When transferred to the operating mode, it is very loud and spectacular “shooting” in TDKS. Sparks fly in all directions. Defective TDKS type 6174Z-8004B. Its cost is 18-22. The schematic diagram of the chassis of the MS-64A is indicated for diagonal 21″ type TDKS 154-375F, the cost of which is 8.5. I installed the 154-375F without any structural alterations. TV has earned. The geometry is normal. Configured SCREEN and FOCUS and all. But there is a drawback. the screen is pretty blue with blue lines arr. move. As a result of shots of a line transformer, Q514, Q513 and Q512 (2SA1266Y) in the amplifier failed. (Instead of 6174Z-8004B in another LG TV, the CF-21D70 was 154-375E. Sellers also offer analogs of the 154-194D (10) and HR7906.)
LG CF-21D70 (Chassis MC-64A). By pressing the button “Network” dezh indicator. mode lights up for 2-3 seconds and goes out. PSU voltages when a button is pressed “Network” have nominal values for 1 second, then they gradually decrease to 0V within 1-2 seconds. (Horizontal scan does not start while the dezh. mode indicator is on, because the TV presses the button “Network” should be included in the bowl. mode).Malfunctioning button “Network”, which supplies power to the TV only while you press it with your hand. The owner of the TV said that the TV was almost always in deja. mode, i.e. rarely used the network button.
GOLDSTAR CF-21E20B chassis MS-41. Faulty captions, which usually run at the bottom of the frame, double so that it is impossible to read them, the picture itself is of normal quality. I connect the test signal generator, turn on the grid on the input, everything is fine, and on the RF through the antenna jack a strong repetition of vertical lines is clearly visible, it is clear that the fault lies in the radio channel. In the end, the malfunction was localized in the K2559 surfactant filter, replaced by K2550.
Goldstar CF-20F60. The TV immediately enters the operating mode, bypassing the standby mode. Voltage with PSU is overstated. Faulty optocoupler IC801.
Goldstar CF-21C22X chassis MC46A Power supply assembled on STRS6707. In the operating mode, the TV works without comment, but when the TV is switched to St-by mode, clicks are heard from the speakers, the frequency and volume of the clicks can change, then after some time the TDKS starts to twist with sound, that is, it tries to start. The LED lights up normally. I measured the voltage in the power supply unit along the line in St-by, it gave out all 80 volts, but it should give out about 40 volts, that’s why extraneous sounds appeared in St-by. The capacitor in the power supply is faulty, 10 microfarads per 100 volts in the secondary circuit, on the control of the optocoupler.
LG KF-21P10 When you turn on the white screen all over the screen, the reverse beam, the TDA6108 and the zener diode on the 5th foot (IK) 7V5 are faulty.
LG CF-21F30K chassis MC 019A The power supply does not start: replacing the TT2140 lower case transistor with 2SD2499 and TDKS 6174Z-6040C (there is a marriage of TDKS manufactured on 09-10.2003).
Goldstar CF-14/20 / 21A80Y. Fault: the buttons on the TV panel do not work properly. The volume is adjustable irregularly. After replacing the memory chip with a clean one, it worked fine. The programmer reads the memory normally, but gives an error when trying to write. When installing a new memory chip, with firmware from a faulty chip, the panel buttons again stop working. But the old firmware is not required.
Goldstar CF-14/20 / 21A80Y. Fault: in SECAM. the predominance of red, in the PAL norm. Break the capacitor built into the circuit L502, hang 100 pF. In my case, I didn’t even need to adjust the contour
GOLDSTAR CF-20E20B (chassis MC-41B). Fault: 30 minutes after turning on the TV, the sound disappears. With the back cover removed, the TV can work normally indefinitely. The GS8434-16A processor recognizes whether there is a telecentre signal from the clock pulses arriving at pin 17 (ID) from pin 21 of the TA8690AN chip. In the absence of this signal, the sound is muted, the output corresponding to the minimum sound volume is set at the output of the processor sound control. The Q06 transistor (type KT315, it was this transistor that was installed during the previous repair) was faulty in the synchronization data transmission circuit. Who repaired in large quantities Soviet TVs knows this feature of the KT315.
LG-CF 20F39 Fault: vertical line. Open circuit 0.364 microfarad at 400V per line. Capacitor manufacturer. Woo yang
LG-CF14 / 20 / 21G20 / D70 / E60 on the MC-64A chassis. Fault: the power supply is turned off. At first glance, all the details are intact, replacing the ic802 chip and the Q810 C3198Y power supply stabilizer transistor with a zener diode in the database did not work. A thorough analysis revealed a capacitor with an underestimated capacity of C824 4.7x50v. After replacing the capacitor, the unit starts up. By the way, in earlier releases of these models there was a 220.0x5v capacitor, there were no problems.
. Repair took 15 minutes. Of these, I searched for 10 minutes on the PIP board. Krenku 78L08 position number IC7P (very inconspicuous). When measuring at the time of switching on, 4c instead of 8c appeared on its output. After its replacement, everything worked.
LG CF-21J50K, CT-21Q41KE chassis MC 019A Fault: the power supply does not start (shuts). Replacing a lowercase transistor TT2140 with 2SD2499 and TDKS 6174Z-6040C is an analog of HR8656 (if all the conclusions of a lower transistor are short-circuited, you probably have to change the TDKS, there are defects in TDKS manufactured on 09-11-2003) in my practice there are three LG TVs of Russian assembly of different brands but with the same chassis and everyone “are dead” multipliers, and the windings are whole. And the TVs are still under warranty.
LG CT-29K30VE chassis MC 022A Malfunction: there is no image and raster (the screen is black), there is sound, when the accelerating voltage increases, the screen is greenish with reverse lines, when switching channels, the image appears for a second, but without a blue tint and disappears again. Replacing the TDA6107JF amplifier did not change anything, only after a detailed check of the strapping, the D903 diode on the kinescope board was leaked in blue, after replacing it with ours from MTs-2 (it wasn’t native), the image appeared.
LG RT-21FA32X Malfunction: the TV does not turn on from standby mode. It turned out to be faulty C820 200.0×160.
GoldStar CF-20E20 (power supply assembled on STR-S5707). Fault: to turn on the TV from a cold start, it was necessary to press the network button 10-15 times. To eliminate the malfunction, it is necessary to replace two tanks: C820 and C825 both 220.0x35v.
Goldstar CKT-9902. Fault: When turned on, the top of the screen shows a black arrow 5-10 cm wide, the direction of the arrow is from left to right. Beautiful clearly drawn arrow with a head at the end in the form of a crescent. 5 minutes after turning on, the arrow disappears. Cause. 100 volt add-on capacitor in frame scan, installed near the frame microcircuit.
LG CF-21D30 Malfunction: at different time intervals goes into standby mode. Replace C408 and preferably change C311 and C824.
GoldStar CF20A80Y Fault: on the front panel I press the program switch button, anything is displayed, only the channels do not switch. It is necessary to flash the 24С02 memory chip on the programmer.
LG CF-21D31KE. Chassis MC-019. The sound is accompanied by unpleasant sounds, the impression is that either the speakers or the ULF are defective. But verification showed that they are normal. The cause of the malfunction turned out to be a TDA9859 audio processor chip.
LG RT-21FB30M. Fault: no image, black screen, OSD is. The IF signal does not pass, there is no signal on pin 40 IC01 (CVBSINT). broken through transistor Q551 (2SA1980)
Goldstar CF-21A80Y. Fault: AFCG does not work, no signal identification. Faulty GS8334-09C processor. Replaced by GS8434-03B. For compatibility with the native remote control, replace the quartz 4.0 MHz with 3.6 MHz.
Gold Star (MC64A chassis) Fault: after switching on, it jumps to 160V and the internal protection in STR-S5707 is triggered. Cause. S824.
GoldStar CF21A80Y Fault: blurry image (no focus). I checked the voltage with the TDKS-norm, I thought the tube was faulty, just in case I dismantled the kinescope block, the arrester on the focus was oxidized (all blue-green), the copper remained, cleaned the oxide with a brush, the TV earned an excellent picture.
LG CF-20J50K (Chassis MC-019B). Fault: the image is shifted to the right by 10cm, there is color and synchronization. Open C505 (222J) of the filter of the 2nd circuit APChF.
LG CF21F60K chassis 019A Fault: a dark screen, when adding an accelerating weak picture with a reverse beam, there is sound, there is graphics. R456 defective open circuit ABL, after replacing the TV is working.
LG CF21F60K chassis 019A TDA9381PS \ N2 \ 3 changes to TDA9361PS \ N2 \ 4I0793 (from LG CT-21Q42KEX).
LG RT-29FA55RB MC049A Malfunction: the TV does not exit standby mode protection is activated, it is necessary to replace TDA6109J. I tried to replace it with TDA6108J: the TV turned on but after 15 minutes it goes into standby mode, it is necessary to replace it with TDA6109J.
GOLD STAR CF-29C36X. Chassis MC-51B. Malfunction: the TV does not turn on from standby mode, when turned on, the DR indicator LED lights up green, after a second red and so on. If you remove the Q803 (C3228) TV turns on, the lowercase starts, but the screen is dark. Faulty IC351 TDA8350Q. After replacement. “fold” vertically in the image due to an increase in the resistance of the breaking resistor FR359 (10 Ohm-0.5 W) for a supply of 45 V. Replaced, as well as FR351 (2.2 Ohms) for a power of 20 V.
LG CF-21D30 chassis MC-64B. (Power supply is assembled on STR-S5707) Fault: when turned on, the red LED on the front panel starts flashing constantly with a frequency of about 2 Hz, the relay clicks are heard in flashes. The TV does not respond to either the remote control or the control buttons on the front panel. Left turned on in this state. After about 10 minutes a stream of smoke appeared. The fault was found by itself. Smoked a small capacitor C813 470pFh1000 V in the secondary circuit of the power source (rectifier diode B bypasses). After replacing with a capacitor close in parameters, the operation of the apparatus was restored.
LG-CF20F39 (chassis-MC994A) Fault: there is no PSU start, the line transistor 2SD2449 is broken. In the harness I noticed “acquaintances” capacitors from WOOYANG. One of them is 0.334×400 in a cliff. Although TVs have a vertical thread with such a malfunction, but the transistor does not knock out, so I replaced the capacitor with 1600 volts (it is also from WOO YANG).
GOLDSTAR CF-20D70B Fault: there is no color in the SECAM system. As a result of the search, faulty Q512 2SC3198Y was found. Raised the voltage on the 13th output of the processor to 2 volts.
Goldstar CKT-9742. Processor SAA1293-02. Fault: all signs of a malfunction in the MDA2062 memory, (incorrect operation of the buttons on the front panel, etc.). Enter the service using the RS-4 remote control, iterate through the optional bytes with the SERV button, the changes are saved automatically. Optional bytes set similarly SAA1293-03 (as in 4USTST).
GoldStar CKT9745 (PC-91A) Fault: it does not turn on, the relay clicks. Faulty R805.820k in the power supply.
GOLDSTAR chassis MS-41A. We replace the LG8634-02A microprocessor with the GS8334-03B. The only difference is in the RGB binding for supplying signals to the processor.
GoldStar chassis MC-51A. Fault: a second after turning on, it turns off in STBY. The famous 1C7P bank (7808) has nothing to do with it, just like the PIP board itself. After several unsuccessful hours to revive the TV, the IC806 (KIA7809) was found next to the power supply, which produced 4 volts at the output. After replacing KREN8A, it worked.
Goldstar CKT-4822. Fault: no image. Is there sound. The screen lights up only if you add an accelerator. On the TDA3561A processor, it seems like everything comes (they changed it before me, but they did not achieve the result). The problem was in his diet. The device showed the put 12V on the first hoof. It is necessary to replace the electrolytic capacitor 330.0x25V, which stands in front of the Krenka at 12V after the diode (the power comes from the horizontal trance). It should be noted that after the above replacement, the TV worked, but badly. I had to replace several more electrolytes for the nutrition of different cascades.
LG CF 20S10E. Fault: the TV does not enter the operating mode. Composition: ICO LG 20S10E IC 501, TDA 8842 S1. The problem is in the resistor assembly AR02 4.7k 9n in the open: 0 ohm. Replacing the AR02 4.7k build, the TV restored. Also 1204 1184. To the above we can add: the failure of the TV inclusion in the operating mode occurs when the AR02 fails and with AR01. But when the AR01 fails, the memory is always intact! And with the AR02 output, a memory failure may occur, even the failure of the horizontal transistor.
GoldStar CF-20D60B, Fault: the mains fuse is on, the STRS6707 in the power supply has failed. Be sure to check and, if necessary, replace C825, C826. Otherwise, the STRS6707 may fail again.
LG-21Q42KEX chassis MC-019. Fault: there is no horizontal and frame synchronization, there is sound. Replaced processor TDA9361PS / N2 / 4I0793 (OICTMH006C).
GOLD STAR CF-14A80B chassis MC-41B. Fault: reduced number of channels received by the TV. The VH (12V) range on the tuner is constantly on due to the leak of the Zener diode Z003 (7V5) in the Q11 DTA114 key control circuit.
LG CF20E20 Fault: Unpredictably shuts down to standby (via
3.30min.). Reason: loss of capacitance C408 1,0mkF 160V in the filter of the output cascade of horizontal scanning. On a faulty conder, the cartoon showed 42V, after replacing it with 33V. Oddly enough, the temperature of the output transistor was normal.
LG CF-21D30. Malfunction: the TV does not respond to the channel switching buttons, confuses commands from the remote control, periodically goes into standby mode. Faulty m / s EPROM 24С04. Replace with a new one, you can not flash it.
LG PT-53A82T Fault: “fled” mixing, specifically. the red ray on the cross does not come down in the menu option. Faulty STK392-120 datasheet, there are two of them. on a blue and red projector. After the replacement, everything is fine. Attention. a real STK costs about 35.
GOLDSTAR CKT-2190, SHIVAKI STV-206M4, assembled on the PC-04A chassis Malfunction: when turned on, there is no sound and color in the image, it skips programs in the automatic setup, the defect may disappear with heating. After the diagnosis, it turned out: the electrolyte C409 0.22mk dried up on the 5th leg of TDA1940 according to the scheme.
Goldstar SKT-2190. Fault: increased brightness, dimming on the left side of the screen with a change in brightness. Replace C431 2.2x250v (power supply for amplifiers).
LG CF-20F39 chassis MC994A. Fault: went into repair with a dead TDKS, the resistor in the ABL circuit also burned out. TDKS once someone has changed. After replacing the TDKS and R 33k, the TV started up. When measuring voltage pit. the line detected its smooth increase to 150-160v protection did not work. A troubleshooting on the stabilization circuit in the PSU revealed a dead optocoupler IC801. Replaced by PC120, everything went as it should. The line tr-r in this chassis without a radiator, I consider this a defect of LG. eliminate! About WOOYANG capacitors I will not repeat.
Goldstar CFZ-9822. Fault: TDKS 154-177E is out of order. This TDKS has a Booster conclusion. Such a TDKS. deficit. It is possible to change it to the common 154-177J. Minimum alteration: Add 5 turns of an insulated mounting wire to the TDKS core, solder one end to the 3 terminal of the TDKS (92 V from the power supply unit), the second end to the C705 100 x 63 V (booster). Determine the direction of winding experimentally, if you mix it up, nothing catastrophic will happen, just all the secondary voltage of the TDKS will be underestimated. Cut the tracks from pins 5 and 6 of the TDKS and swap them (these are voltages of 12 and 24 volts.) You can not cut the tracks, but raise the resistors connected to them and solder them crosswise. Cut the track from the 4 pins of the TDKS and connect it to the ground. Cut the track from the 7th terminal of the TDKS (do not connect it anywhere, since this terminal is 154-177J. 40 volts) All other conclusions are the same. The number of turns of the wound additional winding changes all the secondary voltages of the TDKS directly. (more turns. more voltage.) If in your case the voltages are too high (or underestimated), adjust the number of turns to your option. I selected the number of turns and controlled the output voltage for the power supply of amplifiers (180 V), and only then checked the rest.
LG CF-20D70 chassis MC-64A Fault: there is no line scan launch. D408 1N4148 turned out to be faulty, although it does not show leakage when checking for leaks, even with a digital device.
GoldStar SF-21E20B. Fault: after 30. 40 minutes after switching on, it goes into standby mode, which is accompanied by a blinking LED on the front panel. Subsequent activation was only possible after “cooling down”, and for a time not more than 30. 40 minutes. The reason is the poor soldering of the terminals of the pulse transformer of the power supply. After soldering all the conclusions, the normal operation of the TV was restored. The defect was discovered only after a thorough inspection of the circuit board through a magnifier.
Goldstar CF-20D70B. Chassis MC-41B. Fault: after several minutes of operation, a group of broken lines appeared in the upper part of the raster, and during operation from the input, such a defect was not observed. The reason was in the IC201 switch chip (LA7222). she “squandered” signal.
Goldstar CKT-9902. Chassis PC-04A. Fault: when switching from standby mode to working, the indicator LED goes out, but the device does not turn on. The reason was in the breakage of the diode D401. It is in the power supply circuit of the output cascade of horizontal scanning. Replaced by the diode D226D.
GoldStar CF-21A80Y, aka CF-20E20B chassis MC-41A. Processor GC8334-09B memory 24C02. Fault: when turned on by the network button, it spontaneously entered the operating mode on channel 89 or 91. The buttons on the front of the TV turned on anything except what they should display. After replacing with clean memory and tuning to channels, everything was restored.
LG chassis MC-64A. Malfunction: after switching on, after a while a popping sound appears and in time with this sound a raster begins to appear, which gradually expands horizontally to full size. D408 (1N4148) current is flowing. It stands next to the well-known capacitor C408 along the ABNORMAL circuit.
GOLDSTAR-CF20A80 (chassis MC-41). Fault: Quiet sound with distortion. The sound conversion from multi-standard to IF = 6 MHz is applied. The 6.0 MHz FSE filter to the 49 leg of the TA8690AN is out of order.
LG CF-20F30 Fault: does not start. Turn off the horizontal scan, connect the control light. BP started up the control light came on, all the voltages appeared. However, it was not possible to identify the fault in the scan. I had to go back to the power supply. It turned out that the lost capacitance of the S824 4.7x50V is up to 2.8mkf
LG Model CF-20F80 Chassis MS-84A Malfunction: Received repair with a malfunction No image The sound is normal, although the service information is displayed normally. At high magnification, a very weak inverse image appeared along with the reverse lines on the SCREEN line on the screen. The cause of this malfunction was the ZD741 8.2V zener diode on the ABL line. After replacing it, the picture appeared, the TV worked fine.
LG RT-21FA72X chassis MC-019. The device after a thunderstorm. Fault: when turned on for a second, an image appears and immediately turns off in standby mode. The TDA9381PS / N2 / 4/0703 processor (OICTMPH006B) is to blame. Successfully replaced by TDA9381PS / N2 / 4I0793 (OICTMPH006C).
LG CF-20K50E chassis MC-019. Fault: does not turn on from standby mode. On the 4 leg, the IC803 (STRF6654) has 13 volts instead of 18.9 volts. Defective C801 (100.0x35V).
Goldstar CF-21E60X chassis MC-64A. Fault: it turns off in standby mode at different intervals. Reason: breakdown of D401 (1N4148) and leakage of transistor Q302 (2SC3198). After the replacement, the TV stopped turning off.
LG RT-21FB30M chassis MS-019A. Fault: TV after a thunderstorm. When turned on, a raster appears, but there is no image or sound. The menu turns on, all control buttons work. The setting is turned on, but finds nothing. The IC01 TDA9381PS / N2 / 3I0792 (OICTMPH010A) processor was to blame. After the replacement, it worked.
Goldstar CF-21C22X chassis MS-46A. The TV does not turn on. When you try to turn on, the indicator turns off, but there is no voltage at the output of the power supply. A punched Q812 transistor (KTC1026) was found in the power supply. There are no changes after replacement. Next, the transistor Q2 (KRC102M) was found to leak (replaced by DTC114ES) and IC807 (KIA7812P) in the open. After that, the TV began to turn on, but when turned off, the raster and sound disappeared, and the scans continued to work. Found transistor Q105 (KRC102M) in leakage (replaced with DTC114ES). The device worked fine.
GoldStar CF-20A80Y chassis MC-41A Malfunction: during a cold start, the TV does not turn on well (from the 10th), the hum of a pulse transformer is heard, as well as an unpleasant hum in the speaker, the output voltage is underestimated. There were dried capacitors in the power supply C815, C820 10.0x100V, C826 220.0x35V
Goldstar CF-20A80Y chassis MS-41A Fault: when the TV was turned off from the wall outlet or by the power button, the factory settings were reset (brightness, contrast, turning the TV on and off), the IC02 24c02P turned out to be faulty
LG RE-29FA33X Malfunction: the image periodically disappears and after 5 seconds. goes to defense. Installed personnel loss. The reason is the cold rations of legs TDKS. all but mounted on rivets. TDKS legs are covered with a plastic frame under a monoplate.
LG CF-20E20 Fault: the TV does not turn on, the LED does not light. Found K.Z. high-power transistor in STR S 5707, 120 ohm leakage in a 4N35GV optocoupler between 4 and 5 legs. S820 220mkf 35v and S825 220mkf na35v- changed their capacities. I replaced everything, the TV does not turn on, the LED does not light. S. measured with a meter S824 4.7 microfarads at 50v. the norm, but ESR is more than 30th, replaced the C824 and the TV began to work.
LG CF-21J50K chassis МС-019А Malfunction: the TV is on, there is no reception on any channel, there is no sound. At a low frequency, the TV works. In the service mode of the TV, as for the selector and the inverter, corresponds to the table data. I checked the data bus and the synchronization bus with an oscilloscope, rectangular pulses filled with a higher frequency are available. The voltage of the channel selector matches. Disconnected IF. selector, filed the inverter from another TV, the image appeared. Using Laspi-TT-03, it is impossible to check the inverter; the signal level is low. Replaced the selector and the TV began to work.
LG CF20E20 Fault: the TV works, but on different ranges with a different period of time, it goes into standby mode. By pressing the program switch button on the remote control, the TV works again 20 sometimes 30 minutes. On the IC01 processor on the 20 leg of AVNORMAL, the voltage changed and put the power supply in standby mode. C408 1.0 x 160 volts, in my case: the c-meter showed normal capacity, and the ESR meter is more than 30 ohms.
LG 20E20 Chassis MC-64A. Fault: the power supply on the STR-S5707 does not turn on. Cause. loss of capacitance C824, which is on the 7th leg of the chip. Apparently this defect is due to a not-so-good place to install it. between the fins of the radiator.