NEC NP-NC900C-A Service Manual page 163

SETTING & ADJUSTMENT
Run TeraTerm. And, setting.
Use "dd" to enter Debug Mode
Use Zoom in & Out to find out Optic Center.(z+ is zoom out, z- is zoom in)
Optical center position wide position to tele position or tele position to wide position the center point need
deviation <5pixel
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10-2