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Crumbtrail TV Forums: TV Equipment: TV Repair Forum:
Hitachi 42LN5400 no power with sdby lit

 
 


techforce
New User


Aug 31, 2017, 3:28 AM

Post #1 of 7 (1176 views)
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Hitachi 42LN5400 no power with sdby lit Can't Post
Is this usually the mainboard or could it be bad LED's? Trying to diagnose further, and there is a connector coming out of the PS board with sets of red/blk and red/wht wires in pairs that goes right into the metal frame near the center of
the panel, about 10 pins total, so I guess that is power for the LED array? Same results if this plug is on or off the board.



jts1957
Veteran


Aug 31, 2017, 9:45 PM

Post #2 of 7 (1164 views)
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Re: [techforce] Hitachi 42LN5400 no power with sdby lit [In reply to] Can't Post
Quote
Hitachi 42LN5400 no power with sdby lit
NO such animal!


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Location: Far, Far Away


techforce
New User


Sep 1, 2017, 1:55 AM

Post #3 of 7 (1161 views)
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Re: [jts1957] Hitachi 42LN5400 no power with sdby lit [In reply to] Can't Post
sorry, it wont power on but standby light lit.


jts1957
Veteran


Sep 1, 2017, 3:49 AM

Post #4 of 7 (1157 views)
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Re: [techforce] Hitachi 42LN5400 no power with sdby lit [In reply to] Can't Post
Your TV may use one of each below (or it may use something totally different).
You have the TV & boards in front of you, all we have is the www .

LG EBT62359778 (EAX65049104(1.0)) Main Board for 42LN5400-UA.BUSYLHR
LG EBT62359772 (EAX65049105(1.0)) Main Board for 42LN5400-UA
LG EBT62878002 (EAX65049107(1.0)) Main Board for 42LN5400-UA
LG EBT62359776 (EAX65049107(1.0)) Main Board for 42LN5400-UA

LG LC420DUE-SFR1 Replacement LED Strips 42LN5300 42LN5400 42LN5700
LG 6916L-1402A/6916L-1403A/6916L-1404A/6916L-1405A LED Strips (10)
LG LC420DUE-SFR3 Replacement LED Backlight Strips (10)
LG 6916L-1385A/6916L-1386A Replacement LED Backlight Strips (10)

LG EAY62810601 (EAX64905401(1.5)) Power Supply / LED Board


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Location: Far, Far Away


techforce
New User


Sep 4, 2017, 7:42 PM

Post #5 of 7 (1144 views)
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Re: [jts1957] Hitachi 42LN5400 no power with sdby lit [In reply to] Can't Post
Thought maybe there was a way to know how to test the LED backlights through the connector while it was disconnected.

Im told its unknown if there is a series/parallel arrangement of the LEDs. The connector has red/blk and red/wht twisted wires on it...and I guess I could assume each pair is an LED strip and stand a pretty good chance of being right ?


jts1957
Veteran


Sep 4, 2017, 8:14 PM

Post #6 of 7 (1142 views)
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Re: [techforce] Hitachi 42LN5400 no power with sdby lit [In reply to] Can't Post
http://www.shopjimmy.com/...odels=Lg+42LN5400-UA

The following is based on Shop Jimmy pictures of strips, You won't know for sure until you've opened and compared with ones inside YOUR panel.

EACH Bulb = 3 to 3.5 volts DC (Let/s say 3 volts)

EACH Strip = 3 volts times number of Bulbs (15 volts per half strip ... 30 volts per two half strips joined together) (Each strip has bulbs in series)

Most likely two pairs of half strips joined together (four half strips) connect to one set of wires (60 volts?)
and
three pairs of half strips joined together (six half strips) connect to the other set of wires. (90 volts?)


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Location: Far, Far Away


techforce
New User


Oct 4, 2017, 1:57 AM

Post #7 of 7 (1079 views)
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Re: [jts1957] Hitachi 42LN5400 no power with sdby lit [In reply to] Can't Post
Wound up applying variable CD to each set of pins one at a time...all the strips lit fine. There was an extra set of wires, so I figured those are some voltage / current monitor returns, so left them alone.

Thx for the replies to my post.


(This post was edited by techforce on Oct 4, 2017, 1:58 AM)

 
 
 


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