Bernina 900 electronic - Upper Thread Tension Adjustment

Upper
thread
tension
thread
down
very
slowly.
The
pernmissible
Check
and
adjust
the
upper
thread
ten-
take-off
speed
is
30
sec
±
10
sec.
for
a
sion
with
settng
weight
No
39808004
ength
of
55
mm
(
length
of
thread
lever
slot
in
frame).
The
thread
contained
in
the
bobbin
case
of
a
new
machine
should
be
used
tor
testing,
Place
the
bobbin
with
3-ply.
white,
left-twist
No,60
sewing
thread
on
the
front
reel
pir
and
thread
as
far
as
Jf
the
take-up
lever
which
is
in
its
hig
hest
position.
IMPORTANT:
Place
thread
into
tensioner
on
right-hand
side
of
the
intermediate
disk.
Withdraw
approxirately
30
cm
of
thread
from
the
bobbin
so
that
the
thread
hangs
loosely
between
reel
pin
(33)
and
guide
eye
(34)
when
checking
the
take-off
speed.
Suspend
weight
on
thread
and
observe
the
take-off
speed.
Thread
tension
is
pro-
perly
adjusted
when
the
weight
pulls
the
Fig.
54
133
34
16
;,it
l
_
Fig
55
29