5. Adjustment of synchronizer
Note:
The following machine positions or functions are controlled by the synchronizer:
1. Change of feeding direction and change of stitch length
2. Sideways movement of needle bar
3. Take-up lever top position/needle „up" position
4. Needle „down" position
This adjustment must only be carried out when compelling reasons exist!
It must be performed with absolute accuracy.
Requirement:
A change of sideways needle bar movement must take place when the needle in its upward movement is
7 mm above the needle plate surface (fig. 13).
When the machine stops with the take-up lever in top position, the take-up lever must have nearly reached
the upper dead center.
Check:
•
Insert a new needle.
•
Remove the presser foot.
•
Turn on the master switch.
•
Select stitch pattern „3" with stitch width „9" and stitch length „2".
•
Turn the handwheel forward by one full turn.
•
Continue turning the handwheel slowly and check the timing of the needle bar
sideways movement.
Adjustment:
•
Remove the folding cover and the housing insert.
•
Loosen fastening screw 34 of cam 35 just slightly (fig. 14).
•
Turn the handwheel a full rotation forwards, then keep on turning it until the needle is
about 7 mm above the needle plate surface (fig. 15).
•
Keep on turning cam 35 very slowly until the zigzag stepping motor switches (fig. 14).
•
Tighten fastening screw of cam 34.
•
Make sure that the lobes of cam 36 rest in the center of the circuit board guides.
Cross-Check:
•
Turn the handwheel slowly and check the timing of the needle bar sideways
movement.
•
A change of feed direction or stitch length must take place when the feed dog has
sunk 0.3+/-0.02 mm below the needle plate surface.
24