Acer AL1721h Service Manual page 21

The step between front bezel and back cover shall be within specification.
Top and Bottom
Back cover & Bezel concavity
0.8mm ≤ A ≤ 1.3 mm
Back Cover & Hinge Cover concavity
0mm ≤ B ≤ 0.5mm
Base & Neck concavity
0mm ≤ C ≤ 0.6mm
Top and Bottom
Back cover & Bezel step
B
Left and Right
Back cover & Bezel step
Left and Right
Back cover & Bezel concavity
0.8mm ≤ A ≤ 1.3 mm
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