Bernina 900 electronic - Correcting Thread Tension

Correction
of thread
tension:
1,
Rotate the thread
tension nut down-
wards (tension reduction) until the
weight rnoves easily The thread bet-
ween the reel pin and the guide eye
must be stack.
2 Rotate the thread tension
nut upward 1s'°
l i
until take-ott
speed attains
the speci-
tied value of 55 mm in 30 ` 10 sec,
3, Adjust the thread tension nut to the
mark on the frame cover.
If the
mark on the
thread tension
nut
does not correspond with that on the
frame cover, loosen mounting screw (146)
of thread lension nut (10) and rotate it
until the
marks match. Now, press
thread
tension nut and shaft against each other
SO that curved spring washer (148) which
is situated between the thread tension
nut and the tension support, is tightened.
This produces a braking effect Tighten
screw (146).
Fig 56
146
148 147 Fig 57
30