JVC 250 - Manual (Page 82)

Chapter 5---Electronics
Model 250 Service Manual 5-27
Figure 5-17 Red image needs vertical adjustment (increase).
If Red is higher than Green at the top and bottom, or lower than Green at
the top and bottom, the Red image may not being centered correctly. This
can be corrected with the centering adjustment (see Model 250 User’s
Guide, Chapter 5).
Figure 5-18 Red image needs vertical centering.
If the Red height pot does not completely eliminate the difference in
height between Red and Green, balance the difference at the top and
bottom. Too much of an difference at the top or bottom makes
convergence procedures harder to accomplish.
4. Repeat Steps 2 and 3 above for Blue while hiding Red.
5. Recheck all Geometry and Convergence settings (see User’s Guide) and
readjust wherever necessary.