QUOTE(roommate @ Jan 22 2010, 09:37 AM)
Thats the latest bug found on v40.
One of our forumer have a steps to overcome it. First u need unlock ur phone. Plug in the charger and switch on the plug (do i need to say this?

). Then only u can locked ur phone. By doing this, no more back-light problem.
if u don't wanna wake up during midnight and still affrid the lcd will spoil for whole night long lid up (the lcd will lid on after full charge), then do as follow:
1. goto Menu > Settings > Phone > Phone mgmt. > Auto. keyguard
2. Change the Keypad autolock period to "None"
This will totally disable the Autolock function (your phone screen will black out but the phone wont be lock), and when u doing charge or after full charge the screen will black out itself afterward and wont stay on... good for overnight charging
But i've run a check on the energy consumtion, when ur phone not in lock mode, although the screen black out, it's current consumption still highier then when it's in lock mode, below the read out value:
1. Phone in lock mode => idling average current use ~7mA (still highier compare with v31 idling in lock current usage ~3mA)
2. Phone screen black out (but not in lock mode) => idling average current use ~25mA
So can be say here is that when the phone not in lock mode, it will still in active and most of it's hardware still not in power safe mode although the screen already black out.
It depend on what u prefer, for me if I do an overnight charge i will turn off the autolock so to overcome the lcd constant lid on after full charge bug, and during normal usage I will activate the autolock function so able to save some battery juice