Memorex MT1191V Service Manual page 9

STATIC CONVERGENCE ADJUSTMENT ( Refer to Figure 3 and 4 )
IMPORTANT: Before proceeding, make sure the location of the convergence magnet assembly on the
neck of the CRT is as shown in Figure 3. The rear edge of this assembly must be positioned 65 mm
from the tip of the CRT base. If not properly positioned, convergence adjustment may be difficult, if not
impossible.
1. Apply dot or crosshatch pattern from Dot/Bar Generator to receiver. Reduce setting of Brightness
and/or Contrast controls to eliminate any blooming in pattern.
2. Observe the blue and red pattern appearing on the CRT screen. Locate the 4 pole magnet rings
and separate their adjusting tabs approximately the width of one tab.
3. Now rotate this pair of magnet rings as a unit without re-adjusting the spacing between the tabs.
This will minimize the separation between the blue and red dots (lines).
4. If the blue and red dots are not completely converged at this point, readjust the spacing between the
two tabs to complete convergence of the blue and red dots (lines), thus producing magenta dots
(lines).
5. If necessary, repeat step 2, 3 and 4 until proper convergence is achieved.
6. Observe the magenta (B/R) and green pattern now appearing on the CRT screen.
7. Locate the 6 pole magnet rings and separate their adjusting tabs approximately the width of one tab.
8. Rotate this pair of magnet rings as a unit without re-adjusting the spacing between the tabs. This
will minimize the separation between the magenta (B/R) and green dots ( lines).
9. If the magenta and green dots (lines) are not completely converged at these points, readjust the
spacing between the two tabs to complete convergence of the magenta and green dots (lines).
10. If necessary, repeat step 7, 8 and 9 until proper convergence is obtained.
To prevent accidental mis-adjustment of the magnets, apply a stripe of paint across all six rings and
onto the neck of the CRT.
DYNAMIC CONVERGENCE ADJUSTMENT ( Refer to Figure 5)
Dynamic convergence (convergence of the three edges of the CRT screen) is accomplished by proper
insertion and positioning of three rubber wedges between the edges of the deflection yoke and funnel of
the CRT. This is accomplished in the following manner.
1. Turn the receiver ON and allow it to warm up for 15 minutes.
2. Apply crosshatch pattern from Dot/Bar Generator to receiver. Observe spacing between lines around
edges of CRT screen.
3. For the misconvergence shown in Figure 5 ( A ), tilt the deflection yoke down and insert wedge A
between deflection yoke and CRT.
4. For the misconvergence shown in Figure 5 ( B ), tilt the deflection yoke up and insert wedge B
between deflection yoke and CRT.
5. For the misconvergence shown in Figure 5 ( C), tilt left side of the deflection yoke and slightly insert
wedge C between deflection yoke and CRT. Then, deeply insert wedges A and B between deflection
yoke and CRT.
6. For the misconvergence shown in Figure 5 ( D ), tilt right side of the deflection yoke and deeply insert
wedge C between deflection yoke and CRT. Then, slightly insert and/or extract wedges A and B
between deflection yoke and CRT.
7. Alternately change spacing between and depth of insertion of the three wedges until proper dynamic
convergence is obtained.
8. Use a strong adhesive tape to firmly secure each of the three rubber wedges to the funnel of the
CRT.
FIG. 4
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