Operator Controls - IBM 3278 Series Maintenance Information

8. Remove the two grounding clips, noting the
positions. of these clips, and install them in
the same positions on the new yoke.
Caution: Do not cut into the yoke wiring with the
clips. Also ensure that the clips are cutting through
the white insulation coating on the yoke core.
9. Before removing the centering magnet assembly
from the yoke, note the orientation of the
centering magnet assembly guides in relation
to the split in the yoke windings. This assembly
must be reinstalled with the assembly guides in
the same orientation or the yoke wiring will
not be positioned properly when installed in
the shield. Remove the centering magnet
assembly by lifting the four plastic tabs, and
install them on the new yoke with the same
orientation that they had on the old yoke.
Caution: Ensure that the centering magnet
assembly guides are lined up with the split in the
yoke winding.
10. Reinstall in the reverse sequence.
11. See that the yoke cable is located at the top
when replacing the yoke assembly.
12. Push the yoke tightly against the CRT bell when
tightening the yoke clamp. Do not tighten the
screw fully until after the adjustments have been
made.
13. Perform all the display image adjustments (see
Chapter 5).
14. Tighten the yoke mounting screw fully after the
adjustment.
6.5 Operator Controls
Operator controls are mounted to the CRT mask
assembly. The mask assembly must be removed
to replace any of the following controls.
6-8
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