Remove the back cover of the set and the light shield, then turn the set
on and inject an NTSC crosshatch pattern signal into the antenna terminal.
Note: The crosshatch pattern will appear clearer if the front of the screen is
covered with a dark cloth.
Cover two of the CRT output lenses with cardboard pieces (or other
non-conductive opaque material) and observe the magnified reflection of the other picture
tube on the back side of the viewing screen.
Loosen the lens retaining wing nuts on the CRT Output Lens and Housing
Assembly.
Move the wingnut in the slot of the uncovered lens to locate the optimum
optical focus (viewing the picture from the back side of the screen), then re-tighten the
wing nut.
Confirm correct focus by viewing the screen from the front of the
set.
Repeat steps two through five to adjust the focus of the two remaining
CRTs.
