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9-12
1. Plug the power cord into a
proper outlet.
2.
Turn the AC master switch to
the ON position.
3. Turn the Tach-Dwell selector
switch to the calibrator (CAL.) posi-
tion and adjust the dwell calibrator
until the meter pointer reads on the
SET LINE.
4. Turn the
Tach - Dwell rpm
switch to the 5000 position.
5. Connect the Tach-Dwell leads;
connect the RED insulator lead to
the primary distributor lead at the
coil. Connect the BLACK insulator
lead to a good ground.
On a car equipped with a tran-
sistor ignition system, connect the
RED insulator lead to the RED
side of the tachometer block and
the BLACK insulator lead to the
BLACK side of the tachometer
block.
6.
Connect the trigger pickup into
the circuit of the first spark plug
in the firing order.
_
7.
Turn the Voltage Leakage unit
control
counterclockwise
to
the
TIMING position.
8. Connect a jumper lead from
the distributor primary to a good
ground.
9. Set the Voltage Leakage switch
to the 20 V position.
10. Connect the Voltage Leakage
test leads; the RED lead is connected
to the battery side of the coil and
the BLACK lead is connected to a
good ground.
11. Remove the high tension wire
from the coil and leave the wire
disconnected.
12. Insert the scope pattern pick-
up into the coil tower and attach
the ground clip to a good ground.
13. Set the scope ground polarity
switch to the POSITIVE ( +) posi-
tion.
B
ZERO
LINE
FIRING
SECTION
INTERMEDIATE
SECTION
FIG. 24-
Typical Scope Pattern
GROUP 9-IGNITION SYSTEM
14. Turn the scope display selector
to the SCOPE CHECK position and
adjust the horizontal and vertical
knobs until the trace appears on the
ZERO
(0)
line (allow about
30
seconds for warm-up before adjust-
ment).
CRANKING VOLTAGE
1.
With the tester connected, turn
the ignition switch ON. Make sure
that the transmission is in neutral
and that the parking brake is set.
2. Crank the engine, observe the
speed and note the reading on the
voltmeter.
If the meter reads less than the
specified voltage, check for the fol-
lowing:
weak
battery,
defective
cables, connections, switch, starter,
by-pass circuit, or ignition circuit to
coil.
If the speed is uneven or slow,
the engine or starting circuit is
defective.
BREAKER POINTS
1. With the motor tester con-
nected, turn the scope display selec-
tor to the INDIVIDUAL CYLIN-
DER position.
2. Remove the jumper lead from
the distributor to ground.
3. Insert the coil high tension wire
into the scope pattern pickup.
4. Operate the engine at 1200
rpm.
5. Observe the point open and
point close signals (Fig. 24).
If
an
unusual point close signal is ob-
tained (an unusual point close signal
is one that does not have a short
straight downward line followed by
a series of closely grouped rapidly
diminishing oscillations) , check for
poor
point
contact,
misaligned
points, or weak point spring tension.
If
an unusual point open signal is
DWEll SECTION
81727-A
(188)
obtained (an unusual point open
signal is one that does not form a
firing line that is straight up and
down) , check for dirty or burned
points, or high series resistance.
COIL
Polarity
1. Remove the jumper lead from
the distributor to ground, if it is
still connected.
2. Insert the coil high tension lead
into the scope pattern pickup.
3. Adjust the engine speed to 1200
rpm.
4. Turn the scope display selector
to the ALL CYLINDERS position,
and adjust the pattern length control
until
all cylinders appear between the
vertical lines on both sides of the
screen.
5. Rotate the pattern shift con-
trol counterclockwise until the last
pattern on the screen appears com-
plete.
6. Observe the patterns, noting if
they are upright or inverted (Fig.
24).
If they are inverted, check for the
scope ground polarity switch in the
MINUS (-) position, battery polar-
ity reversed, coil improperly con-
nected, or incorrect coil.
Primary and Secondary Tests.
To check the coil for shorted or
open windings and for primary or
secondary resistance, calibrate the
Condenser-Coil Unit as follows:
1.
Turn the AC switch to ON.
2. Set the
Condenser-Coil Unit
selector switch at the OHMS posi-
tion.
3. Set the Condenser-Coil ohms
switch to the desired range:
4. Connect the test leads together.
5. Adjust the Condenser-Coil cali-
brator until the meter pointer reads
ZERO on the ohms scale.
6. Disconnect the test leads.
7. Disconnect all leads from the
coil.
SHORTED OR OPEN WIND-
INGS.
1. Calibrate the Condenser-Coil
Unit (the ohm switch should be in
the OHMS position).
2. Connect the test lead, one to
each coil primary terminal. Observe
the polarity.
3. Insert the coil pickup into the
secondary tower of the coil and con-
nect the ground lead of the pickup to
a good ground.
4.
Turn the Condenser-Coil Unit
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Table of Contents
Troubleshooting
