There are four screw bolts that hold the screen back casing to the top elbow of the adjusting arm. By loosening them you can adjust the horizontal angle by a couple of degrees. To get to those bolts, you have to completely disassemble the LCD unit. Putting it back together is quite tricky, as you have to balance the LCD unit somehow as you re-connect all the leads around the frame before slotting the LCD into the housing. It is doable and there are online pictorial guides that I have used.
You may find that the droop is greater than you can correct by that method. The bearings in the top and bottom elbows of the arm take a lot of strain from the weight and counter-springs of the unit, and are lubricated by a couple of odd-shaped nylon washers. Over time, the washers shrink or become worn, and some slack develops in the elbow joints. The steel fabric itself is quite soft and can become slightly distorted if it has taken any knocks. You can tighten those joints to some extent by turning the patent screws clockwise. The screws are two ends of a tension bolt that holds the elbows joints together, but is not the load-bearing axle of those joints. The three holes in the screws are designed to take a special Apple tool which nobody ever possesses. However, you can turn them quite safely using the two points of needle-nose pliers, or by using a couple of 2-inch nails braced across each other. This may straighten up the neck somewhat, and also may reduce any tendency to sag due to the weight of the 17" display.
Rick
You may find that the droop is greater than you can correct by that method. The bearings in the top and bottom elbows of the arm take a lot of strain from the weight and counter-springs of the unit, and are lubricated by a couple of odd-shaped nylon washers. Over time, the washers shrink or become worn, and some slack develops in the elbow joints. The steel fabric itself is quite soft and can become slightly distorted if it has taken any knocks. You can tighten those joints to some extent by turning the patent screws clockwise. The screws are two ends of a tension bolt that holds the elbows joints together, but is not the load-bearing axle of those joints. The three holes in the screws are designed to take a special Apple tool which nobody ever possesses. However, you can turn them quite safely using the two points of needle-nose pliers, or by using a couple of 2-inch nails braced across each other. This may straighten up the neck somewhat, and also may reduce any tendency to sag due to the weight of the 17" display.
Rick