Re: LG Flatron L1750S - Stopped to work
No, on U501's RST pin (7) I have 0V and 5V on pin 8.
Maybe I made a mistake in the first time you asked me the U501's values... sorry about that.
I'll upload the U501's datasheet....
rf.pereira
Member
Last Activity: 09-11-2017, 10:20 AM
Joined: 05-26-2017
Location: São Paulo, SP
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Re: LG Flatron L1750S - Stopped to work
Nothing happened...
5.03V passing through the capacitor and even pressing the power button nothing happened.Leave a comment:
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Re: LG Flatron L1750S - Stopped to work
Thanks [I]piernov[/I] and [I]Th3_uN1Qu3[/I]!
Sorry but I'm sure about the pin number, so I'll upload a picture of Q502 with what I think are the pin's numbers.
Based on my picture:
[code]pins 1 and 3: 4.29V
pins 1 and 2: 5.01V
pins 3 and 2: 0.72V
pin 1 and GND: 5.01V
pin 3 and GND: 0.72V[/code]
Did you mean [B]base of Q502 (pin 1)[/B]? And ground = pin 2?
I have a 33uF/25V, is that ok?
Nothing happens...Re: LG Flatron L1750S...Leave a comment:
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Re: LG Flatron L1750S - Stopped to work
Q502 - kia7042ap
4.29V (first and third pins)
5.03V (first and second pins)Last edited by rf.pereira; 09-07-2017, 07:51 PM.Leave a comment:
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Re: LG Flatron L1750S - Stopped to work
---- U201 ----
AVDD (pin28)- 3.31V
VDDC (pin50)- 1.75V
VDDP (pin47)- 3.36V
HWRESET (pin96)- 1.71V
---- Power button ----
5V on the top 2 legs;
When pressed, goes to 0V.
---- U501 ----
VDD (pin8)- 5.00V
RST (pin7)- 5.00V
---- J704 -----
Couldn't find it.
The connector that goes to panel (LCD) (J702):
0V in all of the pins.Leave a comment:
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Re: LG Flatron L1750S - Stopped to work
Without the mainboard conected, measuring the pins (using the correct numbers):
[code]
pin#: voltage
-------------
p11: -0.03V
p10: 0V
p09: 0V
p08: 0V
p07: 0V
p06: 4.9V
p05: 4.9V
p04: 0V
p03: 0V
p02: 13.6V
p01: 13.6V
[/code]
Could be this difference observed between this values and the ones from the post #8 the indicative of something or is just the normal behavior?...Code:Re: LG Flatron L1750S - Stopped to work
Last edited by rf.pereira; 09-05-2017, 11:20 AM.Leave a comment:
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Re: LG Flatron L1750S - Stopped to work
Any idea?
Is there a way to confirm if the PSU is working properly? Maybe some website that shows the correct voltages to each pin?Leave a comment:
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Re: LG Flatron L1750S - Stopped to work
Thank you for your feedback.
U801 (KIA 78D33F) -
[code]5.02V (IN)
3.35V (OUT)[/code]
Could C207 capacitor (680uF instead of a 470uF) causing this 14.5V?
I had a problem with C105 (lifted pad) but I think I managed to solve. But I'll recheck my solders.Code:Re: LG Flatron L1750S - Stopped to work Thank you for your feedback. U801 (KIA 78D33F) - [code]5.02V (IN) 3.35V (OUT)[/code] Could C207 capacitor (680uF instead of a 470uF) causing this
Leave a comment:
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Re: LG Flatron L1750S - Stopped to work
Hi,
After changed the C207, with the PSU and mainboard connected:
[code]pin1- 0V
pin2- 2.37V
pin3- 0.02V
pin4- 0V
pin5- 0V
pin6- 5.02V
pin7- 5.02V
pin8- 0V
pin9- 0V
pin10- 14.54V
pin11- 14.55V[/code]
The clicking noise desappeared, but pin1 to 4 still with a strange behavor... and the monitor still not turn on.Code:Re: LG Flatron L1750S - Stopped to work Hi, After changed the C207, with the PSU and mainboard connected:
Leave a comment:
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Re: LG Flatron L1750S - Stopped to work
Without any power on the PSU, I measured in it:
[code]pin1 to pin4- 1
pin5- 00.5
pin6- 116.7
pin7- 115.9
pin8- 00.5
pin9- 00.5
pin10- 116.7
pin11- 116.7 [/code]
Now, with the PSU (have yet not changed the C207) and mainboard connected and turning on, I measured in the PSU:
[code]pin1- 1.81 to 2.01V
pin2- 1.72 to 1.91V
pin3- 1.78 to 2V
[B]pin4- 0V[/B]
pin5- 0V
pin6- 1.83 to 2.03V
pin7- 1.8 to 2V
pin8- 0V...Last edited by rf.pereira; 05-27-2017, 07:07 PM.Leave a comment:
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Re: LG Flatron L1750S - Stopped to work
Ok, I will change C207 using a 680uF 25V.
If I did it correctly (I attached a photo), the results were (starting to count from the closest pin to ground):
[code]pin1- 1
pin2- 1
pin3- 1
pin4- 1
pin5- 00.7*
pin6- 1
pin7- 1
pin8- 00.8*
pin9- 00.8*
pin10- 1
pin11- 1
* - shorted[/code]
Thanks....Code:Re: LG Flatron L1750S - Stopped to work Ok, I will change C207 using a 680uF 25V. If I did it correctly (I
Last edited by rf.pereira; 05-27-2017, 09:38 AM.Leave a comment:
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Re: LG Flatron L1750S - Stopped to work
Thank you for your replay.
Yes, I didn't change that one because I don't have the exact same model (470uF - 25V). But I have one that is 470uF - 16V, will it do the job?
Sorry, but how do I check for a short on the motherboard?
And how about the noise? It isn't normal, is it?
Thanks....Leave a comment:
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LG Flatron L1750S - Stopped to work
Hi,
My old LG L1750s stopped working some time ago: it doesn't turn on anymore (even the power LED) and only emits a noise that I'll explain in a moment.
I oppened it to try to figure out the problem, but I didn't found any bad capacitor or something "strange" visible. Even so, I started to follow the steps done in [URL="https://www.badcaps.net/forum/showthread.php?t=8559"]this thread[/URL], but changing the capacitors didn't solved my problem.
But I observed something unusual: when plugged, the monitor emits a clicking noise that stops...Last edited by rf.pereira; 05-26-2017, 11:17 PM. -
Re: New Members - please post your introductions here
Greetings everyone!
I was searching for a solution to my LG monitor and found a thread here that helped me.Leave a comment:
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