Question LG Monitor only works after being switch off and on.

Jan 6, 2021
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Good day to all!!!

I've come across a problem that is really worrying me.

Short Version:
My LG monitor now loses signal/connection when I modify anything such as refresh ratio, resolution or enters in sleep mode. I can only bring it back when switch it off (I can hear the sound of the detection then) and back on. Several apps that used it such as Wallpaper Engine, fail to detect it even when I have signal on them.

The monitor is the LG 27mp48hq (LED, D-SUB and HDMI Outputs)


Full History:
Previously I had this monitor connected with an HDMI to DVI cable. For a long time and I don't remember why, it was the only HDMI cable that managed to give me signal. (Although the error wasn't the same, the monitor only showed black but not the NO SIGNAL pop-up with any other HDMI cable despite quality.). It was a flimsy cable that at first so everytime I moved it it came me a green screen before going without signal or just recovering. I blamed the cable connector.

After bring back to live an older LCD Samsung monitor, I decided to start using two monitors without any problem. The LCD which is smaller 24" and older, does have DVI and HDMI and has no trouble connecting to any of them, with any cable. In fact, when I had both working, the PC always elected the LCD as main.

Yesterday, my LG started to show NO SIGNAL/CHECK CONNECTION. I assumed the cable to had failed. But after trying a lot, I came across it worked on the old LCD.
Then I accepted the grim reality, the HDMI port in the monitor was busted. Desperate I tried to disassemble the monitor but I stopped before long as the front came out with all the screen.
I thought it was too much for my expertise and re-assemble it. No problem.
I tried the D-SUB to see if the damage was total and no, it worked perfect.
I assumed I needed to either take it to get it repaired, or live with an VGA to HDMI converter.

Before doing any of that. Just by chance, I tried again with the regular HDMI cable with the other monitor on...and... it got detected for a second.

From there and through experimentation I came across with this:
*Now it could use any HDMI cable.
*Alone or with other monitor.
*Physically moving the cable does nothing at all.
*The image and quality are the same as always.
*If I do any modification like order of screens, switch refresh rate or resolutions, the signal dies. Without moving anything. I just switch it off and it gets detected again. Then I switch it on and presto. This also works without having other screen.


I know something isn't right because previous thing that now it can do, but, I have programs like Wallpaper Engine that can't detect the monitor right away.
Powering on the PC or after the screen goes to sleep requires the same procedure.

Any ideas you guys can give me on what is going on?

Thanks in advance!!!
 

Ralston18

Titan
Moderator
Ideas:

Possibly heat related.

The first attempt fails because some component is cold, maybe some capacitor has lost charge/slow to recharge, etc..

Once the LG is warmed up, recharged, whatever - then the monitor works....

Likely will take some specific diagnostic tool and effort to pinpoint or otherwise identify a specific component or at least a specific PCB.

Do no be surprised that doing so will cost more than a new monitor.

There may be other ideas and suggestions offered. I have no problem with that.
 
Reactions: DocZeius
Jan 6, 2021
2
0
10
0
Ideas:

Possibly heat related.

The first attempt fails because some component is cold, maybe some capacitor has lost charge/slow to recharge, etc..

Once the LG is warmed up, recharged, whatever - then the monitor works....

Likely will take some specific diagnostic tool and effort to pinpoint or otherwise identify a specific component or at least a specific PCB.

Do no be surprised that doing so will cost more than a new monitor.

There may be other ideas and suggestions offered. I have no problem with that.
I was afraid it might cost another monitor. I'll be using it as long as I can. You might be on the right track because so far. Today, it came back from sleep mode without having to do that at least one time. I'll keep an eye on that but yeah, I'll start to save for another one.

Thanks for your idea Ralston!
 

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