Ribbon Unit - IBM 1403 Field Engineering Maintenance Manual

5. Tighten the mounting screws and recheck steps 3
and 4.
6. Replace the hammer-unit assembly in the machine
and run test to check print quality.
7. If necessary, reailjust the hammer-magnet assembly
position with the tool. Be sure to retighten the
mounting screws.
Adiusting Individual Hammer-Magnet
Assemblies for Timing and Density
Individual hammer-Hight time should be adjusted only
after adjusting the print-timing dial.
1. Remove the covers and guides necessary to provide
access to the rear interior of the hammer unit.
2. Loosen the individual magnet-assembly mounting
screws slightly, and use the hammer-magnet eccen-
tric adjusting tool (part 451123) to adjust the ham-
mer-magnet assembly until the printed character is
centered on its hammer mark on the fourth copy.
3. Some compromise with adjustment for density may
be necessary. If properly centering the character on
its hammer mark results in too light, too heavy, or
off-pitch printing, try substituting another hammer.
If further correction is needed, try substituting an-
other hammer-magnet assembly.
Ribbon Unit
Ribbon-Drive-Unit Removal
1. Remove the ribbon.
2. Remove the cover from the ribbon-drive unit.
3. Remove the wires to the ribbon-drive unit.
4. Remove the ribbon-drive unit.
a. Loosen the two screws on the right in the upper-
ribbon-casting mounting gib.
b. Remove the three screws on the left in the gib.
c. Slide the drive unit to the left and raise it to clear
the lower mounting bar.
d. Lower the drive unit to clear the upper gib.
5. Reassemble in reverse order, and position the unit
during re-assembly.
Ribbon-Drive-Unit Positioning
1. Locate the sense finger (Figure 34).
a. Engage the shift lever in the right stop position.
b. Loosen the screws in the lower support bar.
c. Position the left edge of the sense finger a maxi-
mum of 14 4 %." (± Ji'..") from the left upper base of
the T -casting on which is mounted the ribbon
spool center.
d. Be sure that the drive unit is as far to the
righ~
as possible in its locating slot when doing step c.
e. Tighten the screws in the lower support bar.
2. Provide free movement.
a. Loosen the screws in the upper-rib bon-casting
mounting gib.
b. Position the gib for a minimum clearance (.003")
to the ribbon casting without binding the casting
as the unit is moved throughout its lateral range.
c. Tighten the screws in the gib.
Ribbon-Skew Adiustment
1. First be sure that the ribbon-drive unit is:
a. Adjusted correctly.
b. Located correctly.
2. To adjust for the ribbon to skew to the left slightly
when unwinding from the upper spool, loosen the
nut on the left-hand ribbon spool center, and push
the shaft to the rear.
3. Adjust the angle of the skew roller (see Figure 34)
on the skew arm so that the ribbon:
a. Corrects to the right.
b. Winds onto the upper spool with the best right-
edge alignment.
4. The eccentric in the ribbon-skew roller should be
adjusted to assure .010" minimum clearance be-
tween the roller and the ribbon when the skew lever
is in the latched position.
Ribbon Shield and Print-Line Indicator Adiustment
1. Open the T-casting, remove the ribbon and set the
print-density control lever to E.
2. Check the adjustment of the ribbon shield and
print-line indicator for the following:
a. That the key on the ribbon-shield support
bracket enters freely into the slot in the right
end of movable base (Figure 35).
b. That the key on the left end of the ribbon shield
enters freely into the slot in the left end of the
movable base (Figure 36).
c. That the ribbon shield is parallel to the top
surface of the movable base within .005".
d. That the inner surface of the ribbon shield is
.006" to .012" from the lower cartridge-ribbon
guide at both ends.
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