Question about LG Televison & Video
Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis.
To some model sets; especially LED back-lighted types; the back-light inverter circuit will be part of the main power supply board [SMPS]. In such cases, the power supply board might need replacement. To some models sets, the back-light inverter and SMPS section circuit will be integrated at its main board itself. If so; the main board should be replaced. To some models of sets, all these section circuit will be integrated at its main board. If this is the case, you have to replace the main board.
Posted on Sep 22, 2016
SOURCE: half screen activated only
When only a half screen is produced, it is usually a upper or lower buffer board, if the top half is blank then it is the upper buffer, and of course if it's the bottom half then it's the bottom buffer board
Posted on Feb 17, 2007
This TV has a network of diodes connected
to a PROTECT-1 line monitored by the control IC. If any circuit pulls
this line low, the control IC turns the system OFF. The diodes act to
isolate all the circuits from each other, its called a diode-OR circuit.
You can troubleshoot by opening a diode which disconnects a circuit from pulling the line low. I had a hunch the EL backlight board was bad, so after opening that protect line the power stayed ON.
I found a bad .068uF 250V cap on the transformer primary, it measured .002uF. I've replaced the cap and the other two on the other transformers just for good measure.
It probably took more time than the TV is worth, but my friend's Mom will be happy, and thats worth it.
I hope this helps, look around for the service manual, it can be found online.
Posted on Jan 15, 2008
Are there any blown caps on the PSB-power supply board. Most sets have sammy boards and they used very shotty caps. If there are no visual clues being a poped cap at the top (X) they simply often do vaporize and dry out. The YSUS-Main and the 2 Y buffer boards control the picture OSD-on screen display. Your not getting any of that. So power supply is where you start first. The YBU-upper and the YBL-lower control the upper and lower OSD the Ysus main control both of them. Usually if you have one in the door you have to replace all 3. But not always. If you were to replace any of the boards I would replace the YSUS-Main, or get the board reworked at a pc repair shop that does board level test and repai. Its more cost effective.
Best Regards and Semper Fi
Posted on Aug 03, 2010
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