Sharp FDD-412A - Page 76

FDD412A/B
4.2.19 Step Motor
(1) Tools and measuring instruments to be used:
#2 Phillips screwdriver
#1 Phillips screwdriver
Small flat screwdriver (for wire removal)
Spring balancer (3 kg)
(2) Disassembling
(a) Remove the PWB according to 4.2.4.
(b) Remove the step motor wiring from the J3 connector according
to
23s
(c) Detach the steel belt from the head carriage and step motor
pulley.
(d) Remove step motor set screws (M4 x.2) to dismount the step
motor.
(3) Assembling
(a) Mount the step motor with the set screws. At this time,
press it in the arrowed direction (Fig. 4.22) and hold it
temporarily.
(b) Engage the steel belt through the head carriage and step motor
pulley.
(i)
(ii)
(iii)
(iv)
(v)
(vi)
Hold the steel belt temporarily onto the step motor
pulley. (Keep the screw slack.)
Fix the steel belt at the carriage rear end.
Secure the steel belt temporarily at the carriage front,
end. j
Engage the spring balancer in a hole at the steel belt
front end. While pulling the balancer straight at
2.0 + 0.3 kg, tighten the screw at the carriage front
end. 7
Move the carriage twice or more over the entire stroke.
Then tighten the screw on the step motor pulley.
Move the carriage again over the entire stroke, and
check
that
the
belt
is
held
taut
and
straight...
(If
the
belt
is
not
taut
enough
or
straight
enough,
repeat
steps
(iv)
and
(v).)
(c) Install the step motor wiring according to 4.2.3 (wire routing
shown in Fig. 4.5).
(d) Mount the PWB according to 4.2.4.
(4) Adjustment
(a) After replacement, perform adjustment according to 4.3.1,
"Head Position (Tracking) Adjustment" and 4.3.2, "0 Sensor
Adjustment".
~70—