Wobble,
Monitors normally do not work when not connected to a good signal! (this is power saving)
"No Signal" then shuts off. This is normal.
Plus in the VGA cable and it starts working again. This is normal.
There is a very tinny amount of power in the VGA cable, not enough to run the monitor, just enough to power a memory chip so the computer can read what type of monitor it is.
I just checked my monitor and it does what you said.
I just checked my desktop and 19" LCD downstairs and when I pull out the VGA, the monitor goes immediately to sleep mode. Green power light turns to Yellow. It pops back on again (and turns to Green) when I put the VGA plug back in. I turn it off and it goes off. I turn it on and it comes back on.
This 28" Hanns-G monitor isn't right. It USED to just stay ON (Blue led) and display a constant "No signal" message when the computer was off or disconnected.
Now it has problems powering on. It goes on and off, on and off. No Yellow light, no standby. Now when I shut off the monitor, I can't get it to go back on. That is certainly not normal. It takes a couple minutes before it will go on again when I press the button.
EDIT: Ok, yeah, and it has problems going into standby when I tell windows to put it to sleep after a certain amount of time. It said "No Signal" with the Blue led, then it turned Yellow for a second, then off. When I wiggled the mouse, it wouldn't come back on. Remember, its connected to a netbook, so BOTH screens went black at the proper time but only this netbook's screen came back on when I moved the mouse.
Come to think of it, I wonder if this monitor was screwed up from day 1. I noticed this guys monitor (when it was at his house) slways used to say "No Signal" with the Blue power led on when his computer was off. Its like it never properly went to sleep. And now we have these issues with it not powering on
EDIT 2: I couldn't get it back on at all after putting it to "sleep". Even after waiting 10 minutes. I pulled out the wall power cord and put it back and when I pressed the button, it came on immediately. Its like I had to clear the monitors memory ok knowing that its supposed to be sleeping.
I heard theres a thing called a logic board and that can be a problem with monitors. I have no idea what a logic board looks like but I'm wondering if thats the problem. Its like the computer has the power to power on and stay on but is too stupid to know what to do. Not very "logical"...