Checks. Adjustments. And Removals; Section 1 Basic Unit; Base; Diodes - IBM 29 CARD PUNCH Maintenance Manual

Chapter 4. Checks, Adjustments, and Removals
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Section 1. Basic Unit
Procedures outlined for removal and adjustment of the
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machine units are intended as guides. Adjustments should
be kept close to the specification, but the procedures
preferred may vary among experienced customer engineers.
88 of program drum. Each backspace should cause
escapement wheel teeth to move 1-1/4 teeth past end of
armature.
2. Position backspace switch to operate with 1116-inch
depression of the actuating arm.
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4.1 BASE
4.3 FRICTION DRIVE
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4.1.1 Diodes
Check diodes for shorts or opens by using an ohmmeter.
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Check the arc suppression RC units by substitution, never
by running the machine with the arc suppressors removed.
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The RC units are highly efficient at reducing destructive
arc.
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CAUTION
Operation of the machine without arc suppressors may
cause considerable damage.
4.2 DRIVE
4.2.1 Drive Motor
Factory lubrication of the motor should last one year, if
normal usage is 40 hours per week. Pil sparingly.
4.3.1 Friction Drive Service Check
The friction clutch should provide sufficient torque to
deflect gram gage 275 to 325 grams when measured in the
following manner. Manually escape the machine until the
hole in the escapement wheel is straight up. Use the 10X
blade in the gram gage. Hold the gram gage in the left hand
(Figure 4-1) and engage the escapement wheel.
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DANGER
Make sure the starwheels are up when checking torque if
high-speed skip feature is installed.
Press the release key and place right index finger on the
10X blade. Gradually release the pressure of the left hand
until only the blade prevents turning of the wheel. Read the
gram gage.
Gram tension should be measured and adjusted after the
machine has warmed up.
4.2.2 Drive Motor Belt Adjustments
4.2.2.1 Belt Tension
Elongated motor-mounting holes permit adjustment of belt
tension for 1/4-inch deflection midway between pulleys.
4.2.2.2 Belt Size
Check part number of belt. A different size belt is used
when machine has print feature.
4.2.3 Backspace Mechanism Sewice Check
Check that 20 consecutive columns of backspacing does not
affect card registration. The actuating arm should be
straight and free of binds so that its spring can return it to
normal position.
To ensure proper backspacing, check escapement arma-
ture adjustments (4.4.1).
4.2.4 Backspace Mechanism Adjustment
1. Position backspace ratchet with its three screws to cause
a card to backspace into column 1 and not into column
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c---,
Knurld w r w uwd
Figure 4-1. Friction Drive Adjustment
29 FEMM (4169) 4-1