Essilor Instruments APH 550, Maintenance Manual, Page: 62 / 78

60
8-1-7 Replacement of joint block assy, leveling adjustment knob assy
and chart stopper
1) Remove the PD case F and the PD case B (refer to 8-1-1).
2) Remove the Leveling adjustment knob assy by rotating it in a counterclockwise direction.
3) Remove the chart stopper after removing the near point chart holder from the chart
stopper and unscrewing 2 fixing screws.
4) Remove the joint block assy by removing the Leveling adjustment knob assy and the
Leveling adjustment spring post first, and then removing the E ring (either one) and the
joint pin.
5) Procedure of the replacement is finished.
Reassemble it with the opposite procedures of the disassembling.
Fixing screws
Chart stopper
Leveling adjustment knob
assy
Near point chart holder
Joint pin
E ring
Joint block assy
Leveling adjustment spring post
Leveling adjustment knob
assy