Husqvarna 1200 Service Manual page 59

N. The stitch length balance of the machine is not correct.
(buttonholes, pattern stitches, letters)
Always use correct presser foot.
1. Check the pre-setting of the step motor of the guide by means of the service cassette (P.41).
2. Check that there is no friction in the feeding mechanism.
3. Adjust the stitch length balance (P.36-40).
O. The automatic thread tension does not work.
1. Check by means of the service cassette the step motor of thread tension.
2. Check the cable connections between step motor and circuit board.
3. Try a new thread tension device, compl. or step motor (P.52).
4. Try a new circuit board (P.48).
5. Try a new LCD-board (P.44).
P. One or both LCD-displays are not working at all or only partly.
1. Check that there is a correct contact between the memo-chip and its socket on the
LCD-board.
2. Check the cable connections between LCD-board and circuit board.
3. Try a new memo-chip (P.45).
4. Try a new LCD-board (P.44).
5. Try a new circuit board (P.44).
Q. One or all of the diodes of the sewing advisor do not work.
1. Check the connection between the guideboard and the LCD-board.
2. Try a new guideboard (P.48).
R. The machine does not alarm when the lower thread ends.
CHECK: Insert the bobbin case without bobbin and let the machine run about 10 revs.
It should now alarm. Insert a full bobbin into the bobbin case and let it run about 10 revs.
The alarm shoulddisappear now. If not.
1. Clean both diodes of the lower thread sensor and the mirror of the bobbin case and
remove fluff. Try again.
2. Check the cable to the lower thread sensor.
3. Replace lower thread sensor,compl.
4. Try a new circuit board (P.48).
5. Try a new LCD-board (P.44).
S. The machine is sewing with the presser foot lifted.
1. Check the cable to the micro switch of the presser foot lever.
2. Check that the peg of the presser foot lever is pushing in the micro switch.
3. Try a new micro switch or measure it according to the service manual (P.18).
4. Check the cables between the circuit board and the LCD-board.
5. Try a new circuit board (P.48).
6. Try a new LCD-board (P.44).
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