Chosen Solution

My PC monitor image flashes once on startup, then stays black. If I wait for around 15 minutes and click on the input/exit button on the monitor. Usually it will work again without an issue. Is this indicate the monitor power adaptor/power supply is failing? My running dual monitor, the 1st monitor, no issue at all. Been using this monitor for 10 years+. It seems like the monitor require “charge up” time in order to boot up without an issue. The model is LG 23EA53 This is the original adapter, no brick, just the UK 3 pin power adapter. 19v 1.3A. I’m able to source a replacement unit locally at around 7USD.

Update (05/18/2022) @nick @oldturkey03 The OEM adapter arrived today and I just replaced the new power adapter, the issue goes away immediately. The monitor can boot up immediately without waiting. The syndrome is very similar like the video below, it has a very soft hissing sound coming from the monitor when using the old adapter, the monitor will power up and flash once. After replace with a new adapter, the hissing sound also gone. The OEM adapter only cost around $4 USD. I save myself 100+ bucks without a need to buy a new monitor. Thank you so much for the feedback and help! Below is the new adapter from 3rd party.

https://www.youtube.com/watch?v=Kwwi06GG

In most cases, this is caused by bad capacitors on the power supply, or the driver board. First thing I would check is the external power supply; reference your original part number for this. I would contact LG first to see if you can buy one directly but if they will not sell it to you check on a site which sells LG parts. However, if it’s something like a Delta unit you can probably just buy it anywhere. If that doesn’t work, check the capacitors for wear on the LCD controller board; that is the second common cause for this issue. If neither work, it is either a bad LED strip, or a bad LCD. If the LCD is damaged, the cost of repair vs. replacement is rarely (if ever) worth pursuing.

@nick @oldturkey03 The OEM adapter arrived today and I just replaced the new power adapter, the issue goes away immediately. The monitor can boot up immediately without waiting. The syndrome is very similar like the video below, it has a very soft hissing sound coming from the monitor when using the old adapter, the monitor will power up and flash once. After replace with a new adapter, the hissing sound also gone. The OEM adapter only cost around $4 USD. I save myself 100+ bucks without a need to buy a new monitor. Thank you so much for the feedback and help! Below is the new adapter from 3rd party.

https://www.youtube.com/watch?v=Kwwi06GG

mirror less when it is black in a darkened room, shine a flashlight beam at an angle against the screen. See if you can make out shapes or silhouetters. If so, its your backlight. Otherwise, remove the back cover and take a look at the power board. Check the capacitors for any bulging or other damage. This could be a power board issue with some mosfet or bad solder joints. Post some good pictures of your boards with your QUESTION. Adding images to an existing question