Maintenance And A D Ju S Tm E N; Static C H Eck; System Condition Test 5.5"-6.2" Delcotron S Y S T E M - Chevrolet 10 Series 1968 Service Manual

ENGINE-ELECTRICAL 6Y-10
the transistors, diodes and resistors within the regulator.
This unit has certain
assemblies.
1. The regulator units are not grounded in the regula­
tor. They are connected to a third lead which is
brought out of the regulator to a ground location.
2. It does not use a thermistor for automatic tempera­
ture compensation, because the quantity of current
handled by the system does not warrant the minute
corrections this unit is designed to make.
3. The regulator itself is not grounded.
4. It is used with an ammeter and a field relay in the
system.
Wiring harnesses are protected by fusible links. A
fusible link is a length of special wire, normally four
At regular intervals, inspect the terminals for cor­
rosion and loose connections, and the wiring for frayed
insulation. Check mounting bolts for tightness. Check
the drive belt for alignment, proper tension and wear.
Because of the higher inertia and load capacity of the
rotor used in A.C. generators, PROPER BELT TENSION
is more critical than on D.C. generators.
Since the Delcotron and its companion regulator are
designed for use on negative polarity systems only, the
following precautions must be observed.
observe these precautions may result in serious damage
to the charging system.
1. When installing a battery, always make absolutely
sure the ground polarity of the battery, generator
and regulator is the same.
2. When connecting a booster battery, make certain
to connect the correct battery terminals together.
3. When connecting a charger to the battery, connect
the correct charger leads to the battery terminals.
4. Never operate the generator on an uncontrolled open
circuit. Make absolutely certain all connections in
the circuit are secure.
5. Do not short across or ground any of the terminals
on the generator or regulator.
6. Do not attempt to polarize the generator.
7. Do not disconnect lead at generator without first
disconnecting battery ground cable.
Trouble in the A.C. charging system will usually be
indicated by one or more of the following conditions:
1. Faulty indicator lamp or ammeter operation.
2. An undercharged battery (usually evidenced by slow
cranking speeds).
3. An overcharged battery (usually evidenced by ex­
cessive battery water usage.).
4. Excessive generator noise or vibration.
Described below are a series of on-the-vehicle quick
checks which are designed to assist the service techni­
cian in locating troubles within the various components
of the engine electrical system. Additional checks, ad­
justments and overhaul procedures of these components
are also described in the " Charging Systems-Service
Operations Section' ' and
necessary.
STATIC CHECKS
Before making any electrical
following static checks:
differences from the other
MAINTENANCE AND ADJUSTMENT
Failure to
should be referred to as
checks, perform the
gauges smaller than the circuit it is protecting, used
in circuits that are not normally fused such as the
ignition circuit. The same size wire with a hypalon
insulation must be used when replacing a fusible link.
The links are located in the engine compartment wiring
harnesses and each link will be identified with its gauge
size. On most models there is a 16 gauge, red wire
fusible link installed as an integral part of the positive
battery cable or located between the solenoid battery
terminal and the junction block.
(TE 40-50-60, T T 40, TD-TG 50-60) this link is a 14
gauge, red wire. School bus models have an additional
link (16 gauge, red wire) located in the battery feed
circuitry between the engine generator and forward lamp
harness connector and molded splice junction.
1. Check for loose fan belt.
2. Check for defective battery.
3. Inspect all connections, including the slip-on con­
nectors at the regulator and Delcotron.
NOTE: Do not short field to ground to check if
generator is charging since this will seriously
damage the charging system.
SYSTEM CONDITION TEST
(5.5"-6.2" DELCOTRON SYSTEMS)
This test is used to indicate the overall condition of
the charging system (both good and defective) and to
isolate the malfunctioning unit if the system is defective.
1. With ignition off, perform
Checks outlined in this section. Then set hand brake
and shift transmission into neutral.
2. Connect a voltmeter from junction block on horn
relay to ground at regulator base.
CA U TIO N : Be sure meter clip does not touch a
resistor or terminal extension under regulator.
3. Connect a tachometer on engine.
4. Models equipped with Indicator Lamp: Turn ignition
switch on " ON" position and check indicator lamp.
If almp fails to glow, perform appropriate tests and
corrections (Indicator Lamp Circuit Tests) before
continuing.
Models equipped with Ammeter:
switch to " ACC" with an accessory on and check
ammeter. If ammeter fails to read discharge, check
ammeter circuit before continuing.
5. Models equipped with Indicator Lamp: If lamp glows,
start the engine and run it at 1500 rpm or above.
Check indicator lamp. If lamp fails to go out, per­
form appropriate test and corrections (Indicator
Lamp Circuit Test) before continuing.
Models equipped with Ammeter: If ammeter reads
discharge, start the engine and observe ammeter. If
meter fails to move toward charge (from original
position), perform appropriate test and corrections
(Field Circuit Tests) before continuing.
NOTE: At this point a field circuit has been
established and any other problem will lie in
generator or regulator.
On tilt cab models
(Refer to Battery.)
the prescribed Static
Turn ignition
CHEVROLET TRUCK SERVICE MANUAL