User Guide

2-15
Remove the CRT
Removal of the CRT is next. Prepare a soft surface to set the CRT on. Remove
the screws attaching the CRT to the bezel, and then remove the CRT. Do not lift
or carry the CRT by the neck or yoke assembly. Avoid contact with the anode
button, which may still have some residual charge on it, (you may wish to
discharge it again at this point). Set the CRT on the prepared surface.
Several other preliminary compatibility requirements should now be assessed:
• Position the CRT so the face is accessible, providing a soft cushion for the
neck and the yoke if they must rest on the work surface. Alternatively, set the
CRT face-up in an office-type plastic waste basket, making sure that the tube
is not resting on the neck (The small thin part of the CRT is the neck). Place
the touchscreen on the face of the tube, and check to see that the face of the
CRT and touchscreen are about the same size, and that the radius of curvature
(ROC) of each surface matches well. If both of these conditions are not met,
you may not have the proper touchscreen for the display. Most color displays
have standard size CRT's with standard ROC's, and Elo has touchscreens for
most of them.
• Next, determine if the touchscreen will fit in the bezel without modifications
to the bezel. Modifications, if necessary, should be done without
compromising the mechanical integrity of the display.
• Lay the touchscreen face-down in the bezel, being careful not to damage the
transducers. Leave the degaussing coil in place, if present. The degaussing
coil is a hoop, often located between the CRT and bezel, approximately
0.25-inch (6 mm) thick, with a two-wire cable and connector. The coil was
probably unplugged from the power supply earlier.
If the touchscreen will not fit flush against the lip of the bezel, do not force it.
An interference fit between the edge of an IntelliTouch touchscreen and some
of the plastic ribs found in display bezels can pinch and break the small wires
which carry the signals along the edges of the touchscreen or even result in
fracture of the glass after reassembly.
It may be necessary to cut these ribs and struts inside the bezel. Cutting these
ribs and struts does not usually cause difficulties although the stiffness of the
bezel may be reduced slightly. Try not to cut into the posts for the CRT
attachment screws. Bezel and tube combinations that require this cut are rare.
Generally, a total clearance between the edge of the touchscreen and any ribs
or struts of at least 0.25-inch (6 mm) in both axes is necessary. This prevents
the interference fit problem discussed above and allows for variation in
touchscreen mounting position.