Roland Advanced Jet AJ-1000 Service Notes page 201

By tightening Upper Adjustment Screw, the pully is tiltes
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leftward. And, belt moves down.
By loosening upper Adjustment Screw, the pully is tiltes
rightward. And the belt movesd up.
By this way, adjust the belt position on the left side of the
machine.
When the adjustment is completed, tighten up the 2 screws
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shown in the figure on Rail Guide.
<Front View>
Upper Adjustment Screw
<Front View>
Upper Adjustment Screw
<Front View>
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