Chosen Solution
After replacing the screen of a MacBook classic, the computer starts with the monitor to sleep. No backlight . Led on. When the OS is loaded you can wake up the monitor with the classical methods , and it work fine . Suggestions?
Could you try to boot the MB with the installation disk of from another source than your internal drive. That would tell you if the problem is a hardware or software problem. Also why did you replace the screen ? Was the MB dropped or something ? Any problem to charge the battery ? I wonder if the battery Connector/Sleep Sensor could be the culprit ? MacBook Battery Connector/Sleep Sensor (Energy Star)
Try going to System Preferences - Sleep mode - and check the settings
Start without the connector/sleep sensor don’t fix the problem .
