Re: LG 55LN5700-UH dimming every 2 seconds...
The End...
Thank you sir budm!
niswanger
Roy Niswanger
Last Activity: 11-03-2015, 08:54 AM
Joined: 10-15-2015
Location: Round Rock
-
Re: LG 55LN5700-UH dimming every 2 seconds...
No change...exact same behavior. ???Leave a comment:
-
Re: LG 55LN5700-UH dimming every 2 seconds...
Okay that was easier than I thought. Here's what I did...see attached image. The gauge wire is really thin so just having it tinned made for a good pin-connector on the female side of the connector. So in effect the P801 LED+/- connections are now swapped.
I wanted you to see this to warn me of any issues before I apply any power and test.
Thank you,
Roy...Leave a comment:
-
Re: LG 55LN5700-UH dimming every 2 seconds...
Okay I observed really close again...largely the left side dims and when that occurs there are horizontal lines about 1/2" apart or less and they too are more pronounced starting at the far left edge and gradually disappear around 2/3rds of the way to the right.
I'm not creating pig-tail jumpers to swap the LED +/- on P801...I may not have time to complete this test tonight.
Thanks,
RoyLeave a comment:
-
Re: LG 55LN5700-UH dimming every 2 seconds...
Screen behavior is always the same as I describe and posted video in my OP. Remember the screen dims slightly (mostly on the left side of the screen) about every 2 seconds for a period of about 1 sec. So during any voltage test the condition exists. I figured 10 seconds was enough...probably went through at least 4 dimming cycles.
Thanks,
RoyLeave a comment:
-
Re: LG 55LN5700-UH dimming every 2 seconds...
Measured P801 both LED - (negative) leads to Chassis GND for 10 seconds each and read constant 35VDC...once it went to 34.9VDC.Leave a comment:
-
Re: LG 55LN5700-UH dimming every 2 seconds...
Black prob on chassis GND and red probe on LED+, measure for 10 seconds? Record and stop? Or do I do the same for the other (second) LED+ (thinking this doesn't matter from your statement about LED+ tied together).
I know I'm being picky...but I'm just wanting to be 100% sure I know exactly what you are asking to be done. I'm in no hurry
Thanks,
RoyLeave a comment:
-
Re: LG 55LN5700-UH dimming every 2 seconds...
On P801 I see LED+ LED- LED+ LED- Set my multimeter to DC volts on range of .1 resolution. Then probe + lead on LED+ and - lead on LED - (two left ones) and then do the say on the LED+ LED- on the two right ones. Just take note of voltage over 5 seconds for each? What voltage range and fluctuation would I expect to see?
Thanks,
RoyLeave a comment:
-
Re: LG 55LN5700-UH dimming every 2 seconds...
Check post #5, I have a macro shot of the board model. So that yellow/orange'ish board smack dab in the middle is the power supply-LED driver board correct?
I did find those MOSFETs you mentioned in the second image you posted in your second to last post. I don't believe I have revealed that board yet since there's a metal cowling covering it.
So no way to prob or test voltage at P801 for any fluctuations etc? I should just go ahead and make the jumpers ("and label them") and test...Leave a comment:
-
Re: LG 55LN5700-UH dimming every 2 seconds...
Some quick thoughts here before I head off to the office.
First, I found Q803 and Q805 on the second picture attached in your last post. Is that one board for driving both the right and left sides? Is this board the power supply-LED driver board?
I'm going to have to solder jumpers off the back of the P801 connector and back-probe the jumpers to swap the connections to test this. Too bad the connector configuration wasn't + - - + instead of + - + -
Any suggestion on a good all white image? Right now I can...
Leave a comment:
-
Re: LG 55LN5700-UH dimming every 2 seconds...
budm,
Thank you. I only took a quick look and I couldn't find Q803/805 on the main p/s board. I understand you thinking and found P801 connector. There are 4 pins +/- LED so I guess the best way to swap is to unplug and then use a needle to prob and somehow swap them? Thinking here is that if the behavior follows to the right side then it could be an issue on the main ps board? If the issue remains then it could be the LED controller and/or LEDs?
Also, that board "LG EAY62810801" is not exactly...Leave a comment:
-
Re: LG 55LN5700-UH dimming every 2 seconds...
Looks like posts have edit expiry...too bad it's not more like 12 hours. Anyway, here's some more info. Attached is a close up of the p/s model printed on the board.
Notice the top line says REV 2.0 but the the second line says PCB: EAX64905501 (2.2). Just checking over on shopjimmy.com and all I found is one that says (2.0) [url]http://www.shopjimmy.com/catalogsearch/result/index/?q=EAX64905501%282.0%29[/url]
So I'm itching to test and rule out the p/s first if that's possible. Hopefully that's where the...Leave a comment:
-
Re: LG 55LN5700-UH dimming every 2 seconds...
Thanks budm,
Been busy with real work. Here's a start...a lot different than a Panasonic Plasma I tried fixing. I'm assuming there are more boards under the large metal panel?
Attached are the images.
Thanks,
Roy...Leave a comment:
-
Re: LG 55LN5700-UH dimming every 2 seconds...
Guys any good starting point here?
Thanks,
RoyLeave a comment:
-
Re: Is my Panasonic TC-P42X3 PS Bad?
I just removed the 3 bad MOSFETS from my original SS board. They have Printed on them RJP30H2A. The same MOSFETS on the new board from the same locations (new board does have one extra) are DG301.
Can I remove the DG301s from the new 50" SS board and put them in the place of the RJP30H2As?
Also, it takes a lot of heat on the heat bridge of the back plate to get these MOSFETS to lift. Are they easy to damage with de-soldering and re-soldering? Is this an normal practice to re-use these components?
...Leave a comment:
-
LG 55LN5700-UH dimming every 2 seconds...
Hey gang,
I picked up an LG 55LN5700-UH that has an issue and I figured I would have a go at trying to repair it.
I've searched here and I have some ideas but didn't really want to hijack any existing threads. Didn't find any of this exact model.
Attached are the model sticker and software version. And the last youtube video link is a short video of this exact set showing the issue.
The set software is up-to-date and the behavior of the screen dimming every 2.5 seconds and then going back to normal and while the slight dimming occurs... -
Re: Is my Panasonic TC-P42X3 PS Bad?
Alright, well I thought I was a detailed oriented person...attention to detail! Well, I'm not in this case. I found this for a great price so ordered it: [url]http://www.ebay.com/itm/TNPA5313-Panasonic-Sustain-Board-/301772121691?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2047675.l2557&nma=true&si=mA%252FRNWyxIEDTH3s1AALjomXs0UA%253D&orig_cvip=true&rt=nc[/url]
It came in and when I went to bench test the MOSFETS all were good but thought it was odd that it had one extra mosfet (see attached images). Then after I...Leave a comment:
-
Re: Is my Panasonic TC-P42X3 PS Bad?
So I found a used board pulled from a working unit for about the same price as ordering these components. Again, testing like I did is correct for these 3 MOSFETS mounted, that is + lead on the center leg and - lead on the right leg which was a short. Do I have to confirm these MOSFETs are indeed bad by removing them and testing them out of ckt?
What's the likely hood of replacing the SS board and the SC board in my case causing the new SS board to go south?
Thanks,
RoyLeave a comment:
-
Re: Is my Panasonic TC-P42X3 PS Bad?
Okay, I know I have a 720P model. I just checked P11 pig tail from the SS board (that's the one on the right side viewing from the panel from the back with the top at 12 o-clock) and the Vsus pin to ground (chasis) was a short. I checked P2 pig tail from the SC board (left side of panel) and it was in the meg-ohm range.
So it's a short somewheres on the right side of the panel. From the looks of it I need to unscrew the I/P board to access the whole SS board (it's a long board running along the right side of the panel (again from...Leave a comment:
-
Re: Is my Panasonic TC-P42X3 PS Bad?
Yes P1 has from top to bottom 15Vc, GND and then Vsus. So good idea, just use that pig tail connection to test.
This model date is Feb. 2011 and again is the 1080P TC-P42X3
I'll post what I find when I get to it. Thanks for your help and freakaftr8's initial help.
-RoyLeave a comment:
No activity results to display
Leave a comment: