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Crumbtrail TV Forums: TV Equipment: TV Repair Forum:
LG 42LB5600 stand by power only

 

 


JTLiuzza
New User

Dec 1, 2020, 1:48 AM

Post #1 of 5 (216 views)
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LG 42LB5600 stand by power only Can't Post

Novice here.

My LG has 3.5V at all the right pins coming out of the power supply. The 12V and 24V pins have nothing which I believe is correct when the TV is off.

The TV will not come on via remote or manual power button. It seems to me the main board is not signalling the power supply to power up the 12V and 24V pins. I could be wrong as I'm new at this.

What part of the main board is responsible for signalling the PS to power up after an "on" signal is received?

Any insight would be appreciated. Thanks.



jts1957
Veteran


Dec 1, 2020, 7:05 PM

Post #2 of 5 (202 views)
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Re: [JTLiuzza] LG 42LB5600 stand by power only [In reply to] Can't Post


Quote
What part of the main board is responsible for signalling the PS to power up after an "on" signal is received?


The Power button or Remote signals the proper microprocessor input pin(s); the microprocessor then signals the Power supply to turn 'On' (or enable) from the proper output pin.

The above presumes that ALL necessary Power supply voltages are present and that microprocessor is NOT receiving any shutdown signal(s).


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Location: Far, Far Away


JTLiuzza
New User

Dec 1, 2020, 9:03 PM

Post #3 of 5 (191 views)
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Re: [jts1957] LG 42LB5600 stand by power only [In reply to] Can't Post

Thanks, jts.

The one I'm dealing with is an LGE8220. They're available but I didn't want to just swap it out. In the mechanical realm the last thing you want to be is a guy who just swaps parts out and hopes for the best. I could just buy a whole replacement board and say I "fixed" the TV but really I didn't do much and certainly didn't learn anything.

Anyway, I was hoping to maybe get the datasheet for the particular chip and find out where the appropriate "power on" signal comes in, and the signal to the PS to power up comes out, then measure to see if they're present when I hit the power button.

I figure if there's no signal into the chip when I hit the power button, then the chip is not the issue and I have to back up further to see where the signal is stalling. If there's a signal going into the chip but nothing coming out, I know the chip is a dud.

To me (novice) that seems like the right approach.

Trouble is, darn it all if I can't find the datasheet for the thing.

Two things:
1- is my approach a correct one?
2- where on earth can I find a datasheet for the thing?

Thanks for helping out a noob.


jts1957
Veteran


Dec 1, 2020, 11:02 PM

Post #4 of 5 (189 views)
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Re: [JTLiuzza] LG 42LB5600 stand by power only [In reply to] Can't Post

P201 pin out IS stenciled onto both sides of the Power Supply board.
PWR-ON & DRV-ON are clearly labeled.Unimpressed


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Location: Far, Far Away


JTLiuzza
New User

Dec 1, 2020, 11:21 PM

Post #5 of 5 (185 views)
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Re: [jts1957] LG 42LB5600 stand by power only [In reply to] Can't Post

Thanks for the reply. Sorry to put you out.

 
 
 


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