Printronix P4280, Maintenance Manual

Page: 114 / 298

5–32 Replacement Procedures
Hammer Spring Assembly (Figure 5–13 )
Removal
1. Prepare the printer for maintenance (page 5–3).
2. Remove the shuttle frame assembly (page 5–72).
3. Remove the hammer bank cover assembly (page 5–22).
4. Remove three 5/64 inch socket head screws from the old hammer fret.
5. Using the pointed end of the nylon stick supplied in the hammer spring
replacement kit, carefully pry the old hammer fret off its mounting pins
as shown in Figure 5–13 .
6. Discard the old hammer fret and mounting screws.
Installation
IMPORTANT
FRET ONE is on the RIGHT END of the hammer bank as you face the
hammer springs. FRET SEVEN is the LEFT END of the hammer bank.
If you accidently bend the wrong hammer, do not attempt to rebend the
hammer and do not install that fret.
Make sure the hammer bank surface under the fret is clean before
installing a new fret. Dirt or debris between the fret and hammer bank
can cause misalignment, degraded performance, or damage to hammers.
1. If you are replacing one of the inner frets, go to step 2.
If you are replacing fret seven, bend the left–most hammer spring as
shown in Figure 5–13 before removing it from the box. If you are
replacing fret one, bend the right–most hammer spring as shown in
Figure 5–13 before removing it from the box. Go to step 2.
2. Remove the new fret and mounting screws from the box.
3. Install the new fret on the hammer bank mounting pins and press it into
position with the flat end of the nylon stick supplied in the hammer
spring replacement kit.
4. Install the screws from the replacement kit. Torque each screw to 8
±
1
in–lbs in the order shown in Figure 5–13 .
5. Install the hammer bank cover assembly (page 5–22).
6. Install the shuttle frame assembly (page 5–72).
7. Return the printer to normal operation (page 5–86).