TV LG 65UM7470PSA Display Doesn't Turn On
Hello, people.
My TV has gone bad about a month ago. At first it wasn't turning on from the standby state, so I replaced the mainboard. (The mainboard has a humming to it, but I believe it is normal Coil Whinning)
Now... With the new mainboard it does turn on, however, my display isn't working properly, It doesn't turn on when I turn the TV on.
I measured the Power-On voltage on the P201 connector, it has ok voltage when in standby (0V, according to specification), however when I turn the TV on it should have 3V+. The other pins that has voltage on the P201 should be 7.8V on standby and 13.2V when the tv is on. However, they all keep the same voltage at 7.8V, regardless of the TV state.
Also measured the voltages across the mainboard. When it is on the Power-On voltage goes to 3.3V (which is right), however the other voltages stay at 7.8V (as if it was at standby mode)
After checking the above, I went and measured the LED Power connector. The LED+ is measuring something around 300 and the LED- something around 130V. Also, something strange happens! When I connect the probe to the LED- the backlight turns on, is it normal?
Finally I checked the voltage in the "green" component (check picture, I believe it is a voltage regulator) and it measured 30~40V.
Now I'm thinking... Do I need a new powerboard? Did my LED Strips gone bad? I don't know what else to test.
Please Help!
Thank you all, in advance.
My TV has gone bad about a month ago. At first it wasn't turning on from the standby state, so I replaced the mainboard. (The mainboard has a humming to it, but I believe it is normal Coil Whinning)
Now... With the new mainboard it does turn on, however, my display isn't working properly, It doesn't turn on when I turn the TV on.
I measured the Power-On voltage on the P201 connector, it has ok voltage when in standby (0V, according to specification), however when I turn the TV on it should have 3V+. The other pins that has voltage on the P201 should be 7.8V on standby and 13.2V when the tv is on. However, they all keep the same voltage at 7.8V, regardless of the TV state.
Also measured the voltages across the mainboard. When it is on the Power-On voltage goes to 3.3V (which is right), however the other voltages stay at 7.8V (as if it was at standby mode)
After checking the above, I went and measured the LED Power connector. The LED+ is measuring something around 300 and the LED- something around 130V. Also, something strange happens! When I connect the probe to the LED- the backlight turns on, is it normal?
Finally I checked the voltage in the "green" component (check picture, I believe it is a voltage regulator) and it measured 30~40V.
Now I'm thinking... Do I need a new powerboard? Did my LED Strips gone bad? I don't know what else to test.
Please Help!
Thank you all, in advance.
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