Re: LG 42PC1RR-ZL y sus problem
I have a question : here, the job of the TL431 is to stop the rising of the voltage when it reaches the correct value, right?
this job, I think its done. when the Vy is -199, the TL431 reaches th 2.5V and the Vy stops rising
luiznunes
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Last Activity: 05-18-2014, 03:33 PM
Joined: 09-04-2011
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Re: LG 42PC1RR-ZL y sus problem
already turn the pot through it's full range several times and nothing changes.
also removed the cap and everything stays the same. between pin 1 and 3 still 0.6V and Vy -253V.....Leave a comment:
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Re: LG 42PC1RR-ZL y sus problem
well.. too high, but negative.. so too low maybe ( lol )Leave a comment:
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Re: LG 42PC1RR-ZL y sus problem
just to remember, the Vy begins too high ( 250V ) and then drops after 4 or 5 minutesLeave a comment:
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Re: LG 42PC1RR-ZL y sus problem
ok, this is what I measure. between pin 1 and 3, I found 0.6V. when the Vy reaches the 199V ( correct value ) between pin 1 and 3 I get between 2.6 V and 3V. In other words, the TL stays below 2.5 until the Vy reaches the correct value. but why it takes soooooo long to get there?...Leave a comment:
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Re: LG 42PC1RR-ZL y sus problem
pin1, you mean the cathode, right? and measure between the pin 1 and the Vy's GND?Leave a comment:
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Re: LG 42PC1RR-ZL y sus problem
So you think probably it is a bad cap or the TL431, right? I will check it. bu the way, did you saw the pdf with the graphic I posted 3 posts ago?
makes me confused how it can after a while get to the correct voltage.. in the begginnig, at the first seconds the Vy ir right, but after the 5th or 6th second it gets crazy for 8 or 9 minutes.....Leave a comment:
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Re: LG 42PC1RR-ZL y sus problem
I didn't fully inderstand how this dc-dc converter works..
when everything is ok, after 10 minutes, the V on the primary side of the transformer is higher that on the secundary. but at the begginnig, lets say first 6 minutes, it is the oposite..Leave a comment:
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Re: LG 42PC1RR-ZL y sus problem
the values of the output of the transformer are RMS AC valuesLeave a comment:
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Re: LG 42PC1RR-ZL y sus problem
only after 9 minutes the Vy is a stable -200VLeave a comment:
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Re: LG 42PC1RR-ZL y sus problem
Ok, my bad. I must measured the PS102 that time. sorry.
Here I enclose a PDF file showing the evolution of Vy and the output of the transfomer. If you want I can send the excel file with the data.
I was asking about the PS101 and PS102 having the same schematics, so I may compare some values between them....Last edited by luiznunes; 10-09-2011, 09:37 AM.Leave a comment:
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Re: LG 42PC1RR-ZL y sus problem
It shouldn't be stable or shouldn't be around 200?
I can check again.
Isn't the PS101 the same as the PS102? Same component and values except the transformer?...Leave a comment:
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Re: LG 42PC1RR-ZL y sus problem
more or less stable. Why?...Leave a comment:
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Re: LG 42PC1RR-ZL y sus problem
I measure the output of the transformer and is a stable 210VLeave a comment:
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Re: LG 42PC1RR-ZL y sus problem
ok, thanks.Leave a comment:
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Re: LG 42PC1RR-ZL y sus problem
already replaced. problem remains the same...
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Re: LG 42PC1RR-ZL y sus problem
don't you think that, because of the very slow drop of voltage until it reaches the correct 200V is due to a faulty resistor?Leave a comment:
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Re: LG 42PC1RR-ZL y sus problem
to replace it, I need to un-solder the PS101 from the Ysus, right? because I don't have much access to put an iron there..Leave a comment:
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Re: LG 42PC1RR-ZL y sus problem
hey, you don't have to appologize!
I am the one who's need help!
here it is the pictures. if you can see what you want, please tell me and I take more....Leave a comment:
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Re: LG 42PC1RR-ZL y sus problem
you mean the power supply board, or the PS101 of the Ysus board pictures?Leave a comment:
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