Chevrolet 10 Series 1968, Руководство по обслуживанию

Страница: 458 / 713

ENGINE-ELECTRICAL 6Y-33
Fig. 2 7 i—Transistor Checks
third of the scale. If both readings are infinite, the
resistor is open.
9. Resistor R4: Select an ohmmeter scale on which the
15000 ohm value is within, or nearly within, the mid­
dle third of the scale. If either reading is infinite,
the resistor is open.
10. Resistor R5: Use the lowest range ohmmeter scale.
The resistor is open if either reading is infinite.
NOTE:
This resistor on some applications may
be located in the vehicle wiring harness, and not
on the panel board.
11. Resistor R 6 : An ohmmeter scale on which the 150
ohm value is within, or nearly within, the middle
third of the scale should be used. If both readings
are infinite, the resistor is open.
NOTE:
This resistor is not used on some
amplifier models.
Reassembly
During assembly, coat with silicone grease both sides
of the flat insulators used between the transistors and
heat sink, and also the heat sink on the side on which the
transistors are mounted. The silicone grease, which is
available commercially, conducts heat and thereby pro­
vides better cooling.
Ignition Switch Replacement
1. Raise hood and disconnect battery ground cable from
battery.
2. Remove lock cylinder by positioning switch in “ off”
position and inserting wire in small hole in cylinder
Fig . 2 8 i—Setting Spark Plug G ap
face. Push in on wire to depress plunger and con­
tinue to turn key counter-clockwise until lock cylin­
der can be removed.
3. Remove the metal ignition switch nut.
4. Pull the ignition switch out from under the dash and
remove the wiring connector.
5. To remove the “ theft resistant” connector, the
switch must be out from under the dash as outlined
in Step 4. Using a screw driver unsnap the locking
tangs on the connector from their position on the
switch. Unplug the connector.
6
. Snap the connector into place on a new ignition
switch.
7. Place the switch into position from behind the dash
and install the metal ignition switch nut.
8 . Install the lock cylinder.
9. Install the battery cable to the battery and lower the
hood.
SPARK PLUGS
Cleaning and Regapping
Clean the spark plugs thoroughly, using an abrasive-
type cleaner. If the porcelains are badly galazed or
blistered, the spark plugs should be replaced. A ll spark
plugs must be of the same make and number or heat
range. Use a round feeler gauge to adjust the spark plugs
gaps to specifications (fig. 28i).
CAUTION:
Before adjusting gap, file center
electrode flat. In adjusting the spark plug gap,
never bend the center electrode which extends
through the porcelain center. Always make
adjustment by b e n d i n g the ground or side
electrode.
CHEVROLET TRUCK SERVICE MANUAL