Panasonic DLP PT-52DL52 Service Manual page 38

9.5. Lens focus adjustment
1. Enter serviceman mode and select TEST (C-HCH).
2. Confirms that 3 screws (3) is tightened up.
3. Loosen a screw (1).
4. While watching the screen, adjust the lens focus at the center of
screen by turning ring (2).
5. While checking the whole screen, make fine adjustment. Adjust
the focus to the point showing the best overall balance with the
center of screen kept focused.
6. Tighten the screw (1).
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