-31-
12.
DIAL TENSION
STANDAD
With the presser foot lowered and the thread tension dial set to "4", use polyester thread (#60) to check that the
tension between the tension discs is 33 to 38 g.
ADJUSTMENT
1.
Set the thread tension dial to "4", pass polyester thread (#60) between the tension discs, then lower the
presser foot.
2.
Loosen the adjusting screw on the thread tension regulating nut.
3.
Pull the thread with the tension gauge and turn the thread tension control screw to adjust the tension until it is
between 33 and 38 g.
4.
Tighten the adjusting screw on the thread tension regulating nut.
13.
UPPER THREAD TENSION
STANDARD
With the presser foot lowered and the thread tension dial set to "4", use polyester thread (#60) to check that the
total tension of the tension plate and the tension discs is 44 to 54 g.
ADJUSTMENT
1.
After adjusting the dial tension, pass polyester thread (#60) between the tension plate and the tension discs,
then lower the presser foot.
2.
Pull the thread with the tension gauge and turn the thread tension control screw to adjust the tension until it is
between 44 and 54 g.
1
1
3
4
2
polyester
thread (#60)
33- 38g)
tension plate
tension discs
1
1
polyester thread (#60)
44-45g
Summary of Contents for BL7800
Page 1: ...4 2001...
Page 4: ...2 1 MECHANICAL CHART...
Page 9: ...7 1 DISASSEMBLING AND REASSEMBLING THE OUTER PARTS AND MAIN PARTS 8 2 LEAD WIRE ARRANGEMENT 19...
Page 15: ...13...
Page 17: ...15...
Page 19: ...17...
Page 21: ...19 2 LEAD WIRE ARRANGEMENT...
Page 43: ...41 Main PC board...
Page 44: ...42 Power supply unit Power 120 Power 230...
Page 45: ...43 Operation board Other PC boards...
Page 46: ...BL7800 T1010141...