The Lead Screw Assy (#130) (Cat No. 507F34616) is located inside the Internal
Drum and on the Central Mechanical Beam. Its function is to move the carriage
on which the Dynamic Optics are located from side to side. The Lead Screw Assy
contains the Carriage Motion system, the Stepper Motor, the Home Position Detector
and the End Position Detector.
Spare parts for the Lead Screw Assy include the left bracket and the left bearings.
Move the roller (#158) to End Position. This is important to allow free
passage of the carriage along the lead screw.
Power off the imagesetter using the control panel ON/OFF switch.
Open the left and right service doors.
Remove the light-proof cover from both sides of the unit.
Dismantle the fiber optic connector. Place an optics cover over the tip
of the cable. Secure the cable in a safe place where it will not be damaged.
Disconnect the cable harness from the mainframe . Remove the two cable holders
and take them aside.
Disconnect the ground cable.
Use the lead screw handle to move the optics carriage to the middle of the
drum.
Dismantle the stepper motor. Follow the instructions in the section below.
Be careful to pull out the cross adaptor that connects the stepper motor to
the lead screw.
Dismantle the screws that hold the left side bearing housing (#108, #44,
#126).
Gently pull the lead screw, with the optics carriage attached, until the
bearing is out of the right side bearing housing. Pull the assembly out by
grasping the optics carriage. Do not grasp the lead screw!
Pull the assembly until the carriage is out of the drum but still resting
on the center beam.
Assemble the Lead Screw holder (280B34179) onto the dynamic optics coupling
(#131). Tighten it well. This jib holds the lead screw with the carriage after
removing the fork.
Pull out the lead screw with the carriage, and place it on a lint free cloth.
(The cable's length is the limit!)
Disassemble the Lead Screw holder from the carriage. Separate the carriage
(dynamic optics) from the lead screw.
Do not allow any oil to touch the lead screw or the guide beam (#92).
Check the new lead screw for any bending in the thread or visual damage
to the screw. Check that the carriage roller is clean and not damaged and
is not scratched. If so, use the finest grade sandpaper with oil and clean
with alcohol only (not aceton!)
Assemble the lead screw to the carriage.
Fasten the lead screw holder to the carriage. Tighten the cup in a way that
the lead screw will not fall from the carriage and will not be damanged during
assembly.
Put the assembly in place on the guide beam. Be careful when you push the
lead screw into its final position so as to fit the bearing to the housing.
Enter the right bearing into the housing from the right side of the machine.
Assemble the left side housing. Do not tighten the screws.
Push the adjustment pins into their holes in the bracket. Use the adjustment
plate to fit the bracket in its correct place and tighten the screws.
Clean the cross adaptor (#146) of old grease. Put new grease on it and assemble
it into its place. (Grease cat no. 480A10030.)
Assemble the stepper motor in place. Follow the instructions in section
9.4.7 below, Replacing the Stepper Motor Assembly.
Reconnect the fiber optics cable and the electronics harness to their original
place. Reconnect the ground and the cable holders.
Use the Lead screw handle to move the carriage to the home position. Make
sure that the "flag" (#206) enters the optical switch smoothly.
If not, adjust the location of the optical switch. Make sure that the harness
does not catch in the lead screw left plate. Check that it is not too tight;
this may cause the carriage to flip up, causing bad exposure and registration.
Repeat this procedure with the end position detector.
Power on the machine. Run DIAG/UTIL/MECHANICS/CARRIAGE to move the carriage
from side to side. Make sure that the movement is smooth and the harness does
not catch in the lead screw left plate.
Run DIAG/MOTOR/CARRIAGE/Feed Position to adjust the home position detector.
Replace all of the light-proof covers. Close the service doors. Make sure
that the harness does not catch in the lead screw left plate. Check that it
is not too tight; this may cause the carriage to flip up, causing bad exposure
and registration.
