Question: This is not a problem but I want to know what's going on with my LG L91A 19" monitor. I've been using this monitor for the last 3 years and I have no problems with it. Recently I realized something strange: 

After I use my computer, I always switch off my multi-outlet electrical socket which provides electricity for my PC, external HDDs and monitor to make sure that there is no electrical flow through the system. While I was staring around the monitor, I realized by chance that the on/off light on the bottom-right corner was flashing *every 15-20 seconds*. It flashes in a pale blue color. Normally when the monitor is on, it is always on with a strong neon blue color. First I thought that this could be due to the capacitors, but after ***a few hours*** the flashing was continuing as I checked it. I observed this situation several times. Another thing I realized yesterday was that a few minutes later as I cut off the electricity, the monitor's screen flashed just for a split second in a semi-bright gray color. I thought that it is some kind of electrical discharging but I'm not sure. Is that normal? What's going on inside my monitor?

My multi-outlet electrical socket is something like this:

![alt text](https://i.stack.imgur.com/4JV3s.jpg)

Answer: 
Are you sure that the Monitor is still plugged to the multi socket? Sounds like the monitor is taking the energy from somewhere else because I can not think that a capacitor can maintain the led on/off [and the electronics to detect that there is no signal] for hours.

EDIT 1:
Your last comment makes me think that what I said about some energy coming back from a third device is true. No need to be an UPS, just a device with big capacitors that can give energy back. Try to unplug not the monitor but the other devices to see when the monitor stops flashing and you will get the one that is giving energy to the monitor. Just try

[He says that this is what is happening and asks if it is normal]

EDIT2:
Yes, its pretty normal. Devices have capacitors to do several things. [Making it simple] Capacitors store electrical energy inside. When you stop the devices the capacitor has energy inside and probably the output of the capacitor is opened due to the switching off so the capacitor releases its energy by its input. Nothing bad can happen, for sure, its a normal operation
I agree that this might be an electrical discharge.
Do you turn off your monitor before you cut the power? If no, please do turn it off first. I can imagine such side effects from directly cutting power...I have a TV (flat screen), which is brightly flashing and sounds like it just imploded if I directly cut the power without shutting it off first.