Re: Dead LG flatron M1717S monitor
What about what I mentioned before:
When I plug the monitor to the AC power, without pressing the ON/OFF button. The power light is permanently blue ON. Even without connecting the monitor to the PC!!!!.
The ON/OFF button is not functioning.
Does this mean it is the main board problem now?....
shamooooot
Member
Last Activity: 02-14-2017, 12:32 PM
Joined: 11-16-2016
Location: Amman
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Re: Dead LG flatron M1717S monitor
You mean T302, no it is not this is caused by touching it by mistake with the soldering iron.
The opened joint also has no pins to be in it, so it is not a problem.
Thnx for answering.....Leave a comment:
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Re: Dead LG flatron M1717S monitor
Hey Budm
Sorry for the delay.
You were correct by disconnecting J1 I now got a steady voltage. But the power light is permanently ON, even if I don't connect the monitor to the PC!!!!.
The ON/OFF button is not functioning the power light turns ON when I plug the monitor to the AC power!!.
Nothing appears on the monitor at all (no welcoming screen, and nothing from the PC)!!....Leave a comment:
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Re: Dead LG flatron M1717S monitor
Der budm
Yes I was extremely careful in installing.
Yes I replace the two small caps.
With load I mean the connection to the main board. I installed the jumper directly after the MOSFET....Leave a comment:
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Re: Dead LG flatron M1717S monitor
Hello budm
I have replaced those MOSFETs. When I plug the monitor now, nothing is shown on it as before. Also the LED on the ON/OFF button keeps flashing with blue color.
I have tested the output of the power supply board, and the voltage is fluctuating. The results as follows:
Without load: 4.7-5.25 for the 5V rail. And 13-15 for the 15V rail.
With load: 1-5 for the 5V rail. And 6-17 for the 15V rail!!!!!!!
What do you think?....Leave a comment:
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Re: Dead LG flatron M1717S monitor
BUDM
Yes I have left the J1 and now the short circuit is gone.. I tested the U303 and all pins are shortened together. I will get a replacement one soon.
Just for being sure, would my monitor work without connecting the jumper - without backlight of course?....Leave a comment:
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Re: Dead LG flatron M1717S monitor
Dear Budm
I am truely sorry, please excuse me if I offended you in any way.
I just couldn't trace that diode to the inverter circuit
.
By MOSFETS you mean U303, and U304?.
Also as I mentioned before I don't have the 5v rail, I only got around 1v....Leave a comment:
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Re: Dead LG flatron M1717S monitor
Dear Budm
Regarding to your first question, all the marked pins are shortened together and at the same time shortened to the ground (on the output connection).
This short is not resulted from the output as I test the board with the output not connected.
The soldering is bad yes, but I am sure it is not the problem, and these two Schottky diodes are tested fine off board.
And the D201 I don't believe it is related to the inverter circuit!....Leave a comment:
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Re: Dead LG flatron M1717S monitor
Dear budm
Thanks for answering, and sorry for the late reply. I just started to loose hope with the forum.
I have taken a better pics for the board, I also marked the shortened place. Please note that the Schottky diode itself is tested fine off board!!.
Someone proposed that it is obviously the transformer, but I am not convinced as I heard these are very hard to break down. Is there a way to test it using the DMM?.
...Leave a comment:
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Re: Dead LG flatron M1717S monitor
Any ideas pleaaaaase???!Leave a comment:
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Re: Dead LG flatron M1717S monitor
I have replaced the two small electrolytic caps. But still no success....Leave a comment:
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Re: Dead LG flatron M1717S monitor
Thank you for answering STJ.
I have a question,
I removed the Schottky diodes, and I found pins place on board are all shortened!!. While Following on board connections, only two of them should!.
I also removed a 980ohm resistance on the output, and found pins place on the board also shortened!.
All the components on this side seems good (not shortened).
Is this normal?...Leave a comment:
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Re: Dead LG flatron M1717S monitor
I am just wondering if this is a hopeless case!!, could it be fixed or not?Leave a comment:
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Dead LG flatron M1717S monitor
Hello Guys
I had this LG flatron M1717S monitor for a quite some time now. Couple of days ago it stopped working, it is completely dead and even the LED is not working.
I have some experience in fixing boards but when it comes to SMPS I am not very good.. But in this particular case it is a challenge for me to fix this.
I found the output caps leaking and I replaced them all, but still no success.
The bridge is producing 319 VDC.
I took the power FET and test it out (using dirty test), and it seems to have no problem
The voltage... -
Re: New Members - please post your introductions here
Hello Dears
This is Shamooooot. I am a biomedical engineer, my hobby even before I studied engineering is to fix stuff.
I am now working as a service engineer.
I found this great forum and I think it is a great place to get help to fix electronics at component level and stop being slave to the companies which needs you to replace the whole part (board).. I just hate that.
Let the fun begin..Leave a comment:
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