When turning on the ImageWriter II, the carriage assembly moves to the left and then back to center. At this point, the color ribbon assembly rotates counter-clockwise, causing the ribbon frame assembly to drop. As the color ribbon assembly rotates counter-clockwise, it hits a small copper tab called the ribbon shift spring tab.
When this tab is hit, it causes the color ribbon assembly to reverse rotation and lift the ribbon frame assembly back up to its normal position. Using the carrier shaft as a reference axis, the tab is about 45 degrees from the axis.
If the tab gets pushed away from the carrier shaft more than 45 degrees, it is not in its proper position to reverse the rotation on the color ribbon assembly. Thus, the ribbon frame assembly remains down and will not come up to its proper position.
To cure this, push tab back towards the carrier shaft, until it causes the normal change of rotation and let the ribbon frame assembly come back up to its normal position.