Laptop screen takes time to light up

So this is something that rather... baffles me. I recently had to get my screen changed on my asus n82j, and the tech ordered the exact same one. However when my laptop has been closed long enough for it to cool down (i.e about more than an hour) if i open it while it runs on the battery, the screen works flawlessly. If i open it plugged in the AC or if i plug in the AC after it has started it up, it takes about... 2-5 minutes for the screen to actually work, and then it flickers for about 10-15 seconds. After that while, it works completely flawlessly even if i unplug it, replug it, put it into sleep mode for travel or even close it completely down for a mere matter of minutes (the max it went being closed down without problems is about 30 mins.

I haven't checked drivers, i am at work and will check it when i get home, but my previous screen had no problems, so i honestly doubt it has to do with drivers (although updating wouldnt hurt). I haven opened up the screen case and haven't noticed any problems... and on the long run there is absolutely no problems, it really is just a mere startup issue.

it,s not a BIG problem, but lets face it, i'd rather it not become one and it is still annoying.

thank you in advance.