I have two Lenovo T440s laptops. Both have same system model/rev. Both have Windows 7 Enterprise installed. Both are deployed with the same OS image and driver package, using SCCM.
When I connect an external display to the computer (not using docking) using the VGA port, the internal and the external display gets black - nothing happens. I hear the "pling plong" sound, so the machine detects the external display. But as I said, both displays goes black. The power button on the external is green, but goes orange/yellow when I connect the VGA cable to the T440s machine.
I have tried Windows+P, before and after connecting the VGA cable.
I have tried all poosible screen resolution in Windows.
I have tried the latest Graphics driver from Lenovo and Intel. The graphic card is a Intel 4th gen 4200 family. Max screen resolution is 1600x900.
The other T440s has no problems connecting to a external displyay using the VGA port. Same Hardware, same system model/rev, same OS and driver package/versions.
Do you guys have any idea what's causing this?