ITC222 Geometry & Convergence Procedures
29
Hints & Tricks
There are a few shortcuts and other hints for the convergence procedures. Following are some
suggestions for reducing convergence time, enhancing convergence capability and providing more
accurate alignment.
C
OLLAPSE
G
EOMETRY
Occasionally convergence is so far off the pattern may wrap around itself. That makes it difficult
for even the Level 2 procedure to return a pattern to acceptable convergence. If the edges are too
far off, go back to geometry, note the settings, then collapse horizontal and vertical size enough to
view the overscan convergence points. Then return to Level 3 Convergence and move the alignment
points to their proper location. Go to only those points that appear to be wrapped or otherwise
distorted and straighten them. At this point ignore proper convergence. Just make certain the points
are not wrapped around each other. In the following picture the very top alignment point, which
should normally not be visible, has actually moved below the alignment point next to the frame.
Unfortunately, once this method is used, Level 2 cannot be used again. All further alignments will
be limited to Level 3. If the wraparound phenomena is observed, continue with Level 2 alignments
until all other areas of the pattern appear as good as possible. Then collapse geometry and proceed
to Level 3, straighten out the wraparound, return geometry to its original settings, then continue with
convergence adjustment using only Level 3.
