Re: Samsung Ln52B750U1FXZA struck by lightning
Can anyone give insight on what usually means if you have no backlights unless you disconnect main board from power board
Redrebel10
Senior Member
Last Activity: 01-02-2022, 05:42 PM
Joined: 06-12-2017
Location: Saucier, ms
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Samsung Ln52B750U1FXZA struck by lightning
Old friend was throwing this away after lightning struck their house. Standby power light is on but no backlights will come on. However when I disconnect the main board from the power boards, the backlights immediately come on. This leaves me to believe problem is with the main board. Any help would be greatly appreciated. -
Re: Sharp lc-43n4000u
If a TV was hit by lightning and backlights will only come on with main board disconnected from power board does that mean main board is the problem?Leave a comment:
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Re: Another LG, 55ln5100 power issues
Thanks for the info will62
Budm. I read your previous post as you wanted me to plug the lcd to tcon while I had the backlights on. However no picture appears, just a lit up screen. I'm just about ready to wave the white flag on this oneLeave a comment:
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Re: Another LG, 55ln5100 power issues
Correct tcon is connected to main board. Using the power button the backlights will not come on. Unplugging the TV while power is on and plugging back in the backlights come on and all readings are normal while backlights are on I connected the 2 ribbon cables from lcd to tcon board (yes screwed down) voltage on both ends of tcon fuse are 11.3Leave a comment:
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Re: Another LG, 55ln5100 power issues
With both ribbon cables detached from lcd. TV plugged in and hit power button. Backlights do not come on so no voltage at tcon fuse. Same set up, both ribbon disconnected but tcon connected to main board. I unplug TV from the wall and plug back in. Backlights come on and stay on and now have 12v on both sides of tcon fuseLeave a comment:
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Re: Another LG, 55ln5100 power issues
Help.Leave a comment:
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Re: Another LG, 55ln5100 power issues
It was set to 200 DC, guess that's irrelevant since backlights only work with tcon unplugged...Leave a comment:
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Re: Another LG, 55ln5100 power issues
At this point just curious to know why backlights come on with tcon unplugged...Leave a comment:
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Re: Another LG, 55ln5100 power issues
OK so I did another tcon test, I left it plugged into main board and removed both ribbon connectors going to panel. Unplugged TV and plugged back in and the backlights stayed on. I touched my meter to the fuse on tcon to see if it had 12v and the back lights went out immediately. Could have been a coincidence I supposeLeave a comment:
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Re: Another LG, 55ln5100 power issues
Update, got new (used main board installed) still had 3.5v standby voltages, powered on and no backlights came on. Only voltage readings on psb were both 3.2 standby and pwr-on and dvr-on both read 3.2. I unplugged the TV while on and plugged it in and backlights flashed on for a second. I then unplugged the tv and disconnected tcon board from main board. After plugging TV back in the backlights came on and stayed d on. All 12v readings were there along with both 24v readings. Pwr on and dvr still read 3.2 and pdim1 reads 1.1
and pdim2...Last edited by Redrebel10; 01-29-2020, 02:11 PM.Leave a comment:
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Re: Another LG, 55ln5100 power issues
Sorry I already ordered a new main board before you posted that...Leave a comment:
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Re: Another LG, 55ln5100 power issues
Well tried the new eeprom (no change) and tried baking the main board for 10 minutes at 385 degrees and still no change. So it looks like I buy a new main board or trash the TVLeave a comment:
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Re: Another LG, 55ln5100 power issues
Thank you to all helping, I will update tomorrow after getting new eeprom and I will try all that is suggestedLeave a comment:
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Re: Another LG, 55ln5100 power issues
OK thanks, yes I tested in diode mode same mode I would test a fuse for continuity. So at this stage are you thinking the fix would be replacing the main board?...Leave a comment:
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Re: Another LG, 55ln5100 power issues
Like. 27 on that one but if that controls the standby voltage I guess it's good since I can still get 3.5v on those 2 pins. Gonna try heating up the main board and see if that does anything, have the new eeprom coming in Friday, the main board replacement is 60 so hoping I can find a cheaper fix...Leave a comment:
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Re: Another LG, 55ln5100 power issues
I was going to ask if I needed to take it out of circuit diode, D201 reads the exact same if I flip your neg and positive leads...Leave a comment:
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Re: Another LG, 55ln5100 power issues
Budm. Since losing the standby light and can no longer get the backlights on, I can only get 2 readings on your psb connector and that is both of the 3.5 pins.(top pins)...Leave a comment:
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Re: Another LG, 55ln5100 power issues
Thanks I'll try that when I get home...Leave a comment:
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Re: Another LG, 55ln5100 power issues
I inspected everything under the psb and all looked good. What are the 2 3.5volt pins for? meaning are they responsible for sending power to the mainboard and it triggers all the other voltages?...Leave a comment:
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