Question LG 34UM67-P detects input but says "No Signal" ?


Feb 15, 2020
I have an LG 34UM67-P that will detect the video source correctly (DP, HDMI1, HDMI2, DVI) and display the input info in the top-right corner for a couple seconds as usual, but then it displays "No Signal. Entering the power saving mode shortly." That message displays for several seconds, then the monitor goes blank, then the input type displays again in the top-right corner, then the "No Signal" message again, cycling in perpetuity for as long as the video source is connected.

I own two other 34UM67-Ps so I've A:B tested everything and the issue is definitely with the monitor and not with the source.

One thing I've wondered is if somehow the power saving mode is stepping on the display process, like it's preventing the signal from being displayed. I don't even know if that's possible. The obvious solution to test this would be to turn off the power saving mode. However, without an active signal the monitor presents only a limited menu and you can't get to the power saving settings (you can pretty much just select which input to use).

Is there a way to brute-force my way into the full menu to try changing the power saving mode setting? I've also scoured the web to see if there's a service menu available but haven't found anything. The only button on the monitor is the joystick button at the bottom center of the monitor. I've tried connecting power with the joystick in different configurations to see if I could trigger a service menu, but no luck. There are no reset buttons that I can find anywhere. Maybe inside the case?

My known options right now are to either remove the main board and send it for an attempted repair (~$100 if successful, just shipping if not) or to put the monitor on eBay for parts.

Thoughts/suggestions? Thank you.