Hello all, I'm new to this forum so apologies in advance for any bad etiquette. I read through the forum rules, hopefully I do okay, but anyways here's my situation...
I'm posting this here because I've read many posts that have been helpful thus far in troubleshooting my problem and hope that the electrical expertise can figure this one out for me. I have a LG W2452T monitor that has had issues turning on over the last year or 2. It is almost always running and just goes into idle but the few times it has been unplugged for various reasons it always has issues coming back on. The most recent time I had to unplug and re-plug it in several times before hitting the power button did anything. Most of the times it would just not do anything, no light or anything, when I would hit the power button after plugging it in.
I pulled the board out and tested the voltages and when the power supply is out of the monitor the 5v pins were reading about 6.5V, but when connected to the rest of the monitor it was reading about 3.8V. Nothing comes out the 12V or 25V pins but my guess is that's because the monitor isn't turned on--I haven't tried shorting the PWON and 5V pins for fear that may not be correct (though I've read on other monitors that's how to do it).
After reading several posts I assumed it had to be the capacitors, even though they all looked perfectly fine, so I ordered all new capacitors. When I replaced each of them I tested the old capacitors once out of circuit and the capacitance came back just about perfect on ever one of them. That probably isn't the issue.
In the process however I did find a resistor that registered infinite resistance! That must be it, at least as far as I've gotten to this point. However I have no idea what the value of this resistor is to replace it. That probably sounds pretty stupid because there are color bands but none of it makes sense.
BTW I should quickly note that I went ahead and purchased the service manual for this monitor thinking it would have schematics in it... which it does... however it doesn't include a schematic for the power supply.
I've attached 2 images:
1 - This is not my image, but a very clear one of the power supply board I found online that notes where this resistor is on the board. It is in location R102, which if I could find a schematic would quickly solve this for me.
2 - I've taken several photos of the resistor in different lighting so you can get a clear look at the bands.
All of the value combinations I've come up with don't seem to be logical since it's almost impossible to find resistors of that value. Here are the 2 most likely values I can come up with:
1.06M Ohms 5% - Brown, Black, Blue, Yellow, Gold
146 Ohms 5% - Brown, Yellow, Blue, Black, Gold
In either case I can't find a single retailer that sells a resistor of this value.
There seems almost no denying the middle 3 colors: Yellow, Blue and Black... but the ends are probably more difficult... It would have to end in Brown or Gold... Can't be black or Orange. All though in natural light the one end looks more black in color... not sure that can be the case either since there would be no reason to start a resistor with black... you can start to see where my brain unravels.
Am I missing something here??
I'm posting this here because I've read many posts that have been helpful thus far in troubleshooting my problem and hope that the electrical expertise can figure this one out for me. I have a LG W2452T monitor that has had issues turning on over the last year or 2. It is almost always running and just goes into idle but the few times it has been unplugged for various reasons it always has issues coming back on. The most recent time I had to unplug and re-plug it in several times before hitting the power button did anything. Most of the times it would just not do anything, no light or anything, when I would hit the power button after plugging it in.
I pulled the board out and tested the voltages and when the power supply is out of the monitor the 5v pins were reading about 6.5V, but when connected to the rest of the monitor it was reading about 3.8V. Nothing comes out the 12V or 25V pins but my guess is that's because the monitor isn't turned on--I haven't tried shorting the PWON and 5V pins for fear that may not be correct (though I've read on other monitors that's how to do it).
After reading several posts I assumed it had to be the capacitors, even though they all looked perfectly fine, so I ordered all new capacitors. When I replaced each of them I tested the old capacitors once out of circuit and the capacitance came back just about perfect on ever one of them. That probably isn't the issue.
In the process however I did find a resistor that registered infinite resistance! That must be it, at least as far as I've gotten to this point. However I have no idea what the value of this resistor is to replace it. That probably sounds pretty stupid because there are color bands but none of it makes sense.
BTW I should quickly note that I went ahead and purchased the service manual for this monitor thinking it would have schematics in it... which it does... however it doesn't include a schematic for the power supply.
I've attached 2 images:
1 - This is not my image, but a very clear one of the power supply board I found online that notes where this resistor is on the board. It is in location R102, which if I could find a schematic would quickly solve this for me.
2 - I've taken several photos of the resistor in different lighting so you can get a clear look at the bands.
All of the value combinations I've come up with don't seem to be logical since it's almost impossible to find resistors of that value. Here are the 2 most likely values I can come up with:
1.06M Ohms 5% - Brown, Black, Blue, Yellow, Gold
146 Ohms 5% - Brown, Yellow, Blue, Black, Gold
In either case I can't find a single retailer that sells a resistor of this value.
There seems almost no denying the middle 3 colors: Yellow, Blue and Black... but the ends are probably more difficult... It would have to end in Brown or Gold... Can't be black or Orange. All though in natural light the one end looks more black in color... not sure that can be the case either since there would be no reason to start a resistor with black... you can start to see where my brain unravels.
Am I missing something here??
Attached Files
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