JUKI MF-7800D Series, Engineer'S Manual

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1. Installing the connecting rod MC-36
(1) Taking care of the vertical direction of the connecting rod, fix the top
end of the rod on motor lever
A
using the screw of ball joint , and
fix the bottom end of the rod on pedal lever
B
using the screw of
ball joint . Loosen fixing screws in the connecting rod, and
adjust the length of the rod properly.
2. Adjusting the connecting rod air valve MC-36
(1) Loosen setscrew in the valve holder, and adjust the position of
air valve properly. The standard position of the air valve is obtained
when the valve pin lightly comes in contact with the head of rivet.
(2) Make the sewing machine actuate, and check the response time of
the air valve. If it is too early, separate the valve pin from the rivet
head, and adjust the response time properly.
(3) Once the air valve is properly positioned, securely tighten setscrew
in the valve holder. At this time, check the position of thrust collar
so as to eliminate a play in the spring.
Adjustment Procedure
Results of Improper Adjustment
MC-36