Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
[QUOTE=dick_barton;733475]I wonder if the two blue ceramic capacitors are the problem... QUOTE]
Blue ceramic capacitors were already desoldered previously and are well in their specs...
Banging my head with this
Btw as last resort.. What would be replacement for phase detector ..something I would solder on ? Hmm
Not a expert in this , sorry
Don't wanna put my dmm inside ha ha nor the phase detector but I guess there would be some equivalent stuff maybe..just saying as last resort..Re:
Adriatic
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Last Activity: 04-25-2017, 02:22 AM
Joined: 03-04-2017
Location: Ljubljana
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Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
I did try with a bright background as you suggested and the result is very very good, the bottom half of the screen is perfect (picture 1)
...Seriously I did with white bckg (picture 2) and it looks to me no problem, evenly lit (backlight on max and min).
Did also try with cfl lamp, don't know if I did it correctly IMHO but it seems ok, btw cfl was 18W. At static image cfl shines evenly and at movie it also shines evenly with a small hiccups at the end of the bulb, guess...Last edited by Adriatic; 03-15-2017, 11:47 AM.Leave a comment:
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Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
Thx ... I know that, but to late already tried with cheap Vici vc99 (from EEVBlog only morons buy this meter ) but hay it survived yupiii
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Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
Will check tomorrow. Guess it writes on the panel itself.
Thank you budm.Leave a comment:
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Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
@budm
Tnx. Will try that tomorow. By the way this small load mystery fix only works for down CCFL if I put this "fix" on upper CCFL there is no fun, tv wont work. So you could be right.
It is LG 42LD750 as mentioned in title.Last edited by Adriatic; 03-14-2017, 01:34 PM.Leave a comment:
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Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
Thanks but this tv is a mystery for me. If I put phase detector (picture 1) or DMM on inverter output wires than the TV works (picture 2). It works for hours flawlessly ! It doesn't matter where I put it, on the PSU board or CCFL input jack doesn't matter ...it works every time for hours.
WHY ? WHY ? WHY ?
Anybody smart enough ? Oh and yes there is no error signal from the main board in this case ! Strange !...
Last edited by Adriatic; 03-14-2017, 12:40 PM.Leave a comment:
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Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
Tried and yes the backlight stays on. You are pointing on ... ?...Leave a comment:
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Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
Will try that ...thank you very much for your time BTW...
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Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
If you think this small ones (picture) than yes I did. They are not the same. First one is ok I think all 4 showing 0.62 Mohms. But here is strange thing .. one time I get same readings on first one and not second one(some are's 88 kohms) and vice versa, strange can not get same readings twice ? Not sure what to think about it. They are however reversed on the board. Why I don't know....Last edited by Adriatic; 03-11-2017, 10:14 AM.Leave a comment:
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Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
If I understand correctly those two wires should both be L and on the other side the tv where are only one wires per ccfl is ground ? So I only measured difference voltage between those two hot wires and not between ground and live (hot) ones ? Am I correct ?Last edited by Adriatic; 03-11-2017, 09:50 AM.Leave a comment:
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Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
Already done that
no luck
Actually done that not only on inverters but also elsewhereLast edited by Adriatic; 03-11-2017, 09:45 AM.Leave a comment:
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Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
BTW
If I check resistance (TV off ) the same way I get 0.3 Ohms... not sure that is ok ?Leave a comment:
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Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
@dick_barton
Sorry but I already wrote about this and it is not the case. Without DMM on, TV wont start even if there are probes in TV. Tried several times, because of that I wrote that is some kind spooky. If the probes are in and the DMM on, the TV starts and keep running until I unplug probes from DMM ( from DMM not TV !) the same happens if I turn off DMM.
So my conclusion is that DMM is some kind influencing on TV behavior. How ?
Don't know.Leave a comment:
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Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
Just checked capacitors. All in ranges. So it is not that.
Hmm.Leave a comment:
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Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
Don't know, pulled out all 4 of them for both inverters.
Will try to test them at friend's house with his DMM with extra digit resolution. Fingers crossed.
Can I try to start the board without them ?Leave a comment:
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Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
Will check thank you.
One is SL6KV 10J .. I thinkn 10pF
Second SL6KV 27J .. I think 27pF
Correct me if i'm wrong, <<<<<<<<<<<<<<<<btw having trouble measuring them because resolution of my DMM is 10pFLeave a comment:
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Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
Now this is spooky ?
I recovered PSU board from the dead but only to the point when it starts three times and then stops.
But here is the catch. If I stick probes of DMM to the input of ccfl lamps and set it to AC than TV set starts normally, no shutdown no error etc. It is not pressure or contact related btw and that is what is bothering me. Immediately when I pull out probes from DMM (from DMM not from TV set !) the TV shuts off and show error. Reading are avg at 340V, at start there is spike up to 440V,...
Last edited by Adriatic; 03-11-2017, 06:28 AM.Leave a comment:
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Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
dick_barton
Thank you, hope you are right. Btw that on the picture is green I have spare blue ones 10D471K , hope it will do the job.Last edited by Adriatic; 03-06-2017, 06:29 AM.Leave a comment:
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Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
Btw it is betwen N and L... by the memory .. not sureLast edited by Adriatic; 03-06-2017, 05:48 AM.Leave a comment:
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Re: LG LCD 42LD750 Backlight flashes 4 times, then tv off.
It is marked as VA100 (EL42 and EL20 on the empty holes/pins)
Here is a picure of board where this element is missing.
Thank you...Leave a comment:
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