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C .
Ksv Punch
Perform
A
and
B
Check escape
mechanism
T m
far
No
I
Check drive
g s a
train
+
Check FC torque
Check P I cam contact
Check
FC
torque
or
escape
mognet
onolyre original
foiling condition
I
I
Figure 1-8.
Escapement
(Part 2 of 2)
skips through column 38. This is followed by a 25column
skip (ending in column 63), an llcolumn alphabetic
duplication, a Scolumn skip, and duplication of column
80.
1.4.5 Punch Drive Cycle Failures
Locate punch drive cycle failures with the starwheels raised
(Figure 1-9). Diagnosis of clutch failures should include an
initial manual cycle of the punch drive unit. Incorrect
clutch overthrow or a defective detent can be found while
performing this operation
1.4.6 Printing Control Failures
The program card used for locating escapement failures can
be used for locating programmed printing failures. Diagnos-
tic flowchart is Figure 1-10.
1.5 MACHINE SERVICE FEATURES
The 29 Card Punch has two diagnostic features that have
been incorporated to aid the customer engineer. These are:
Motor switch
Test probe
1.5.1 Motor Switch
The motor switch turns the motor off and allows other
areas of the machine to remain energized. It is useful when
manually cycling the machine. Some adjustments are made
with the motor stopped.
1.5.2 Test Probe
The test probe (Figure 1-1 1) contains a neon indicator in
series with a resistor. One lead of the indicator is connected
to the power supply. The other lead is used to trace circuits
leading to coils or magnets. A jack is provided on the power
supply chassis.
CAUTION
Care must be used when probing relay points because the
point of the probe might spread the pin connectors and
cause the reed switch to make poor contact or break the
pin. Be careful in the use of the test probe; an accidental
short could tack several relay points. The probe should
not be used to estimate circuit voltages. Use the meter for
voltage measurements.
Reed relays should be probed through the top of the
bobbin because the vertical rows of holes on the land
pattern for a particular relay position do not, in all cases,
connect to the relay connector.
Note: When probing P3, a false indication may occur; P3
appears not to make. This is due to the timing relationship
between the short duration of P3 (7 ms) and the 60-Hz
negative line pulse used to bias the probe.
1.6 SERVICING TECHNIQUES
1.6.1 Forcing
Extra pressure can be applied to various components to
simulate malfunction. For example, the friction drive can
be forced or retarded manually at the top of the program
drum, or finger pressure can be applied to the escape
magnet armature to help or hinder its operation. Magnetism
of the escape magnet can be detected, and its strength
estimated with any lightweight steel blade (screwdriver or
burnishing tool).
29 FEMM
(4169)
1-7
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