Re: LG 43LF5900 mainboard failure
update - all three sets were returned to working order by replacing the main board (~50$ each).
wangcheung
Member
Last Activity: 05-08-2023, 06:02 AM
Joined: 01-22-2018
Location: Palmer
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Re: LG 43LF5900 mainboard failure
There is a separate smaller processor that manages the IR functions and power switch and then hands off after the initial power on.
several other devices were lost during the same event, a couple Visio LCD TVs survived though. All were lost through connection to the mains. Surge suppressors weren't able to protect much since this was a lightning strike, although not direct to my house.
it disappoints me that we have become a landfill generation, well not those of us that try and repair equipment, but the norm is to dis...Leave a comment:
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Re: LG 43LF5900 mainboard failure
something I forgot to mention, while reviewing the schematic for the main board I noticed that ALL surge protection components were labeled OPT which I assume to mean optional because NONE of them were populated on the board. I'm not surprised that all three sets failed at the same time. I'm not sure if this is common practice but I would be hesitant to purchase any LG product seeing that cost cutting has left the main components relatively unprotected to save minimal cost. I guess producing landfill is the latest direction for consumer electronics...Leave a comment:
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Re: LG 43LF5900 mainboard failure
ok, all hopes of repair are lost
I was checking all of the power regulator circuits and found that the 1.2V_MTK output was 0 volts when the POWER_ON was present and then realized that the main IC was getting really hot so it appears the main IC is internally shorted.
Thanks again for the service manual Will, that made all the difference having the schematics available. Come to find out the schematic matched for the 43LF5900
I'll keep my eye out for one more main board. Thanks for the tips and helpful discussio...Leave a comment:
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Re: LG 43LF5900 mainboard failure
Hi RDC55, I was skeptical as well. I read in a post on here somewhere that the EEPROM can be updated if blank from ROM but not if corrupt. I was reaching in the attempt and since I have 3 dead main boards I figured I could sacrifice 1. EEproms are cheap.
I had 3 identical TVs that had the same symptoms, bought 2 main boards that brought 2 to life but can't find a third main board so I'm trying to debug the board now.
thanksLeave a comment:
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Re: LG 43LF5900 mainboard failure
Thanks for that Will. I'll check through the service manual now.Leave a comment:
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Re: LG 43LF5900 mainboard failure
I swapped out the EEPROM without any change in function. Guess I'll keep looking for a point of failure.
Thanks for the suggestionLeave a comment:
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Re: LG 43LF5900 mainboard failure
I ordered some EEproms that I think are equivalent. I'll try and replace it on one of the board since I read that a blank will get programmed automagically
nothing to lose here
Leave a comment:
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Re: LG 43LF5900 mainboard failure
I only get PWR_ON (3.3V), no response from DRV_ON when turning on and off the TV. The standby LED works properly when switching from OFF to ON.
EEPROM or flash?
Thanks,
DanLast edited by wangcheung; 01-27-2018, 09:10 AM.Leave a comment:
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LG 43LF5900 mainboard failure
I have 3 dead 43LF5900's that were taken out during a surge (lightning). All three have the same symptoms where the standby LED is on when plugged in and when the set is turned on the LED blinks three times and then turns off with nothing displayed on the screen.
I tested voltages on the power supply board and all are as listed on the power supply board silkscreen including the EN after switching the set on.
I located one mainboard (EBT63838406)and installed in one set and that took care of the issue. Now my problem is that I can't locate any more boards so I would... -
Re: New Members - please post your introductions here
Hi,
new here and excited to find a new forum for assistance with the repair/debug of TV'sLeave a comment:
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