Apple monitor that is plugged into the computer with a parallel port cable.
There is also a Cinema HD display 150w power supply.
When the system has been in sleep mode or hibernation, such as overnight, the wire from the main white cable that is plugged into the back of this power supply has to be removed, re-inserted, jiggled, to get the image on the monitor screen to come on or stop blinking on and off. Once the wire is pulled out and re-inserted and given a shake the monitor works fine for the entire day.
There are 2 other wires in the main cable that have USB connectors but they don't do anything and are not plugged in.
So, the main cable leaving the back of the monitor has 4 wires branching off. One goes to the tower, one to the power supply and the other two with USB connectors go no where.
Why does this monitor stop working and the wire to power supply needing to be removed, re-inserted, and minor shaking.
The power supply is quite warm to the touch, but it is on 24 hours a day forever, so that should not be a factor.