IBM 29 Card Punch Field Engineering Maintenance Manual page 67

4.11.5 Print Drive Adjustment
1. Loosen the left-hand thread screw (Figure 4-49) at the
rear of the punch shaft and position the eccentric to
align its groove with the mark on the print cam (A,
Figure 449).
2. Trip the punch clutch while holding the print sup-
New Wire pression armature attracted and rotate the punchshaft
to 172 degrees on the index. Check for 0.001-inch to
0.008-inch clearance between the print cam and the
print arm roller (B, Figure 449). Rotate the punch shaft
through the rest of the cycle and note that the print arm
roller does not touch the print cam before 180 degrees
on the index.
3. Unhookthe print spring and makesure that the print arm
roller can be lifted 0.010 inch off the cam. If the
clearance is unobtainable, check step 2 of 4.11.2.5.
Wire used as
a guide
4.11.6 Print Suppress Magnet Adjustment
1. Armature should be flat within 0.005 inch (Figure 4-52).
2. Adjust and form the ears of the armature pivot so that
the armaturelies flat against both yokes.
3. Check for 0.006-inch to 0.008-inch air gap between the
armature and the core when the armatureis attracted.
Shim the core, if necessary, using steel shims (part Front End
305271).
4. Form the ears of the armature return spring (flat spring)
Print Wire Restoring Head to require 15-gram to 30-gram pressure to move each ear
Spring orint Wire from the armature; sides must be within 5 grams of each
other. Improper adjustment causes print suppression
— | trouble.
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Figure 4-51. Print Wire Replacement
Flat Armature Return Spring
6. Unhook the code plate return springs. To prevent
omnpmmrencnanl
damage to the print wires, move the pressure plate back Co
away from them. The code plate may now be with-
L
drawn
0.035" to 0.037"
, Armature
Retainer
CAUTION
Whenreinstalling the code plate, see that the shims
do not get out of position. Keep oil and grease off the
code plate back and shim retaining plate; it causes
shifting troubles. When replacing the code plate
return plungers, replace the plungers in matchedpairs
only; they must be balanced within 10 grams of each
other.
4.11.4 Ribbon Feed Paw! Adjustment
Adjust the ratchet stop pawl eccentric to cause ribbon feed
pawl to feed one tooth per print cycle. Figure 4-52. Print Suppression Magnet Adjustment
4-36 (4/69)