Twice in the last couple of days (since installing 10.5.6), my Early 2008 MacBook Pro has gone dark when I've unplugged the power adapter while it's been charging and powered-on. It keeps running fine, but the backlight can't be turned back on, even when I try to change the screen brightness with the keyboard. I can dimly see the brightness indicator change on the screen, confirming that it's hearing my keypresses.
The only way I can restore the display is to restart the machine. Has this happened to anyone else? Only major change was the install of 10.5.6 update a couple of weeks ago. I have had the dreaded NVidia distorted video problem about 6 months ago, but that's not happened since. Machine temperature doesn't seem excessive--CPU is at about 130 F when charging.
Thanks in advance
MacBook Pro 2x2.5 4GB; Mac Pro 4x2.66 6GB, Mac OS X (10.5)