Acer Aspire ZS600 Service Manual page 211

Change the calibration fixture to 9 vertical lines, and do the lineation from left to right with line
from upper to lower to calibrate verticality with the touch pen (Refer to the sequence of 1→ 2
→ 3 → 4 → 5 → 6 → 7 → 8 → 9 and the arrows in the picture above).
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Troubleshooting