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Tube TVs
LG CRT tv failure model 21SB1RL-L4
hace 5 años
hace 5 años
Hello guys good afternoon today I bring you a fault with this tv that only has voltage on its main capacitor (170v) in the b + there are no signs of voltage and the choper does not throw voltages of any kind download the diagram of the board and check each component adjacent to IC810 (STR-W6554A) and all are well ... Except I don't have any. Voltage or D815 line that does not have short ... All its diodes and capacitors are fine
17.741
hace 5 años
Hi. I commented everything done in trying to solve the fault. So do not suggest the same. That is part of the technical report you should do when you can help to collapse more specifically.
hace 5 años
Hello good friend, I performed the basic check, it has a switch and when pressed it does not turn on the standby LED I uncovered the equipment and I started the internal check ... fuse is fine go to the bridge rectifier and it gives me voltage to the capacitor c803 there I It measures 170v, I measured the B + and the voltage is dead 0V unlink the diode that comes out of the choper that goes to the B + and nothing 0V in a few words the source is not working ... I went to the line that powers the ic810 and there is no voltage for pin 4 more for pin 1 there are 170v on the other pins there are no voltages there check each associated component
17.741
hace 5 años
hace 5 años
You have a problem in the line that feeds pin 4. Until you have voltage, the regulator will not work. You have already made the voltage measurement on the form as I understand and there is no tension. Always speaking circuit that is born in the diode bridge. That the colleague told you to control diode and R that you say you have well. If they were, you would have tension. That if the other components are ok. Control printed that is not cut.
Desolder one end of D845 and measure. If it does not appear, the optocoupler is dissolved. And measure if tension appears. If it does not appear. Electrolytics such as C840 and others change for new ones. Comment to continue.
Diagram.
https://dokumen.site/queue/lg-21sb1rl-l4-chasis-cw81bpdf-a5b39f0310047c?&queue_id=-1&v=1576588171&u=MjAxLjI1My40LjIxMA==
hace 5 años
I will do what you tell me to see if I manage to have tension in the printed line that feeds pin 4 of the w6554A
hace 5 años
Hello friends, I comment disconnect the D815 and in diode scale it tells me 440 that theoretically it is a correct value and conversely it does not give value or continuity
17.741
hace 5 años
Inverse measure in resistance scale 200 megabytes. If it leaks there it will tell you. The resistance must measure the same in both directions. That's how I control. And the diodes if I have any doubt, I remove them from the board
hace 5 años
Well folks retracing my steps I checked everything again and it turns out that the initial cut-off switch internally was damaged replace it with one from a donor and the TV manages to turn on ... But now it only blinks at the corners of the screen and it it is black ... It has audio but a beep is heard apart from the usual noise and it is detailed that it does not turn on the filaments of the tube
17.741
hace 5 años
How good you will find the fault. You must close this topic and open another with the current failure.
46.781
hace 5 años
hace 5 años
Unlink the flyback from the source and place a focus of a power equal to or less than the power of the TV as a provisional load of + B until the voltage stabilizes.
Indicate the voltages obtained on each of the source regulator pins in the primary stage.
hace 5 años
There are no voltages at the output of the choper and I unlink the diode that feeds the line of the b + to see if the source came alive and nothing goes on 0v on the ic810 there is only voltage on pin 1 all the others are dead with 0V so I proceeded to unlink and measure each component of the line that feeds pin 4 of the ic810 and all are well
hace 5 años
All capacitors have their nominal values, diode D815 is not short or zener zd845, 47k resistors mark 46.7k each ... But pin 4 does not reach anything, unlink it to see if that voltage appeared and nothing is totally dead
hace 5 años
hace 5 años
it seems that the switch is not working you have to change the STR-W6554A
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