Hello everybody,
I just get a LG L1811S with the green LED flashing 2 times per second.
I managed to get the service manual and uploaded it here.
As you can see in the service manual, there are 3 boards: the power board, the logic board and the inverter.
Here are the tests I performed:
- Power board disconnected from everything: the 12V and the 5V are perfectly stable and there is a fast ticking (I think it's coming from the main transformer, about 5 times per sec.).
- When power board connected to the logic board, the 12V varies between 11.8 to 12.1, and the 5V from 4.6 to 4.7. The sames voltages are going to the inverter. The ticking slows down too 2 per sec, as the green LED.
- When the inverter is not connected, no changes: I don't think the problem comes from it.
- The voltage on pin 1 of U270 (74F14 IC) is from 2.6V to 4.3V. The output of the pin 2 (0.4V to 1.5V) seems to go to the panel board (with the control buttons and the LED) where it varies from 0.3 to 1V after a resistor (I think this cause the LED to blink). I didn't manage to see where the input on 74F14 pin 1 comes from, maybe from the GM2121 IC? I think the problem is upstream.
I followed the "no power" section in the troubleshooting section (but actually there is power!), and at the step 3 the pin 103 of U203 (GM2121, the main IC) is at a solid 2.2V...
I don't really know what to conclude with all this, and what to do next.
Any help would be appreciated!
I just get a LG L1811S with the green LED flashing 2 times per second.
I managed to get the service manual and uploaded it here.
As you can see in the service manual, there are 3 boards: the power board, the logic board and the inverter.
Here are the tests I performed:
- Power board disconnected from everything: the 12V and the 5V are perfectly stable and there is a fast ticking (I think it's coming from the main transformer, about 5 times per sec.).
- When power board connected to the logic board, the 12V varies between 11.8 to 12.1, and the 5V from 4.6 to 4.7. The sames voltages are going to the inverter. The ticking slows down too 2 per sec, as the green LED.
- When the inverter is not connected, no changes: I don't think the problem comes from it.
- The voltage on pin 1 of U270 (74F14 IC) is from 2.6V to 4.3V. The output of the pin 2 (0.4V to 1.5V) seems to go to the panel board (with the control buttons and the LED) where it varies from 0.3 to 1V after a resistor (I think this cause the LED to blink). I didn't manage to see where the input on 74F14 pin 1 comes from, maybe from the GM2121 IC? I think the problem is upstream.
I followed the "no power" section in the troubleshooting section (but actually there is power!), and at the step 3 the pin 103 of U203 (GM2121, the main IC) is at a solid 2.2V...
I don't really know what to conclude with all this, and what to do next.
Any help would be appreciated!
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