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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.
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