LG 42LC46 problem
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Re: LG 42LC46 problem
I see at least one regulator on the board.
Get out your multimeter. Set it to 20VDC. Place the black probe on the metal chassis; for example, a part of the metal frame like a spare screw hole. Then, turn the TV on (and make sure the picture is good.) Measure the voltage on each pin (using the red probe) - for the middle pin, measure the tab as they are connected to each other and it's easier to measure, and report the readings. Then, wait for the picture to go bad, and measure again.
Use a loupe to read the part number and report that back.Last edited by tom66; 01-07-2012, 04:58 PM.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: LG 42LC46 problem
Datasheet: http://pdf1.alldatasheet.com/datashe...K/RT9164A.html
"15" indicates 1.5V output, so we should see 1.5V on one pin.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: LG 42LC46 problem
Okay so the regulator is fine.
Next step:
- turn TV off at wall
- disconnect left ribbon connector (for left side of screen)
- turn back on you should have picture on right but not on left (left hand might be random noise, or just white or black.)
- wait 10 mins does problem occur?
- turn back off, plug left in and repeat with right.Last edited by tom66; 01-07-2012, 05:15 PM.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: LG 42LC46 problem
Okay so the regulator is fine.
Next step:
- turn TV off at wall
- disconnect left ribbon connector (for left side of screen)
- turn back on you should have picture on right but not on left (left hand might be random noise, or just white or black.)
- wait 10 mins does problem occur?
- turn back off, plug left in and repeat with right.Comment
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Re: LG 42LC46 problem
Next test is to leave the set on with ribbons connected until problem occurs, then unplug the LVDS cable, leave T-con for 30 seconds, and plug the LVDS back in, seeing if you get a picture.
Also, do you get sound during failure?Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: LG 42LC46 problem
Strange, never seen that behaviour before, okay that means my test there won't work. (Some t-cons work with half the display, due to marginal components...)
Next test is to leave the set on with ribbons connected until problem occurs, then unplug the LVDS cable, leave T-con for 30 seconds, and plug the LVDS back in, seeing if you get a picture.
Also, do you get sound during failure?
I did your 1st test as soon as picture went so that is probably why half of screen had no picture..there was sound during failureLast edited by sienoki; 01-07-2012, 05:55 PM.Comment
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Re: LG 42LC46 problem
Do you want me to do your 1st test again when the set is cold..cos i only get a good picture for 10mins from cold and when picture goes bad i would have to wait till set cooled down again to get good picture back
I did your 1st test as soon as picture went so that is probably why half of screen had no picture..there was sound during failureComment
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Re: LG 42LC46 problem
Do you reckon the screen itself is on its way out.Comment
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Re: LG 42LC46 problem
I asked the lad at work today what the faults where..he said he was having screen problems going shaded then flickering..after that then the start up issues(bad caps)he never told me about the screen issue when i bought it.
Do you reckon the screen itself is on its way out.
Can you repeat the first test after the set cools down?
Do you have an oscilloscope, or can you borrow one?Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: LG 42LC46 problem
The fault in the pics doesn't look like a screen fault, as the noise is random like digital noise - screen faults cause bands of failure (e.g. horizontal/vertical lines, missing parts of picture, slow updating on one half, etc...)
Can you repeat the first test after the set cools down?
Do you have an oscilloscope, or can you borrow one?)i dont know of any1 i could borrow off.That bloke at farnells said he was a moderator on this site but i didnt get his num or name
anways i will do 1st test againComment
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Re: LG 42LC46 problem
I wont beable to get my hands on any advanced testing equipment so it looks like im stuck with a dead setComment
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Re: LG 42LC46 problem
Since i replaced the bulged caps the set has never been on for longer than 40mins..ive now left if for 1hr with the picture like in quote 14..had 10 cups of coffee cos im dont like getting beat..especially with 90quid in it..anyways after 1hr i turned the set off by the remote(standby)and then turned it straight back on with remote and have been watching a crappy army film with patrick swayze for over 1hr..ehh
So my question is did something on the boards?just need a good charging or something???Comment
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Re: LG 42LC46 problem
Aren't intermittent faults so much fun?
It's doubtful the fault has been fixed. I hope it has though. However in the last week I have had 2 tv's and a car heater fan all with intermittent problems that have magically started working again.. go figure!
JimComment
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Re: LG 42LC46 problem
The fault has not been fixed..after 10mins when the picture goes the back of the set is not warm..it only starts to get warm at about 40mins..then if i turn off and on with remote the picture great for as long as the set is on..
What other tests can be done?
Im thinking solder joints but ive got a jewelers eye and had a really good look..cant see anything obvious..when i borrow a descent camera i will post some close ups of all the boards underneath..thxComment
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