Arm Shaft Circuit; Dismounting-Mounting - Husqvarna 6690 Manual

Arm shaft circuit

Dismounting-Mounting

There are two so-called reader forks in the arm
shaft circuit (7/48) for sensing the position of the
arm shaft. The black disc (7/46) on the arm
shaft obstructs the movement of the step
motors, e.g. there can be no zig-zag
movement as long as the needle is less than 5
mm above the level of the stitch plate. Likewise,
no feed changeover can take place as long as
the feed dog is above the level of the stitch plate.
Remove the flat cable, cable holder (4/37) and
the lamp holder (7/52). The printed circuit is
mounted in a metal holder (7/47), which is held
in place by a stud at the front of the arm and one
screw (7/55). Unscrew the screw and remove the
circuit and holder. If it is necessary, a screwdriver
can be inserted behind the holder to prise it off.
Removal will be easier if the circuit is loosened
from the holder. Dismount the circuit from the
holder and return it for repair.
Mounting is done in the reverse order. Ensure that
the stud is in its hole before screwing in the screw.
Setting the side movement of the needle (zig-zag
movement).
Preliminary setting.
Loosen the set screw (7/44) in the arm shaft disk
and turn the disk until the set screw is
horizontal. Turn the hand wheel until the
take-up lever is at the upper position. Check the
axial position of the arm shaft disc-it should
move freely in the reader fork-and tighten the
screw (7/44).
Fine adjustment.
For fine adjustment see "Requirements" and
"Adjustment" on page 15.
The side movement of the needle shall commence
when the needle is 5,5 mm above the level of the
stitch plate-this applies to both the upward and
downward passage. If the needle turns when the
needle is too low, turn the screen against the working
direction when the arm shaft is stationary.
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