Test 7 - Check Field Boost; Test 8 - Diode/Resistor - Generac Power Systems GP Series Diagnostic And Repair Manual

Section 4 AC Diagnostic Tests
Results
If Continuity was not measured across each wire, repair
or replace the wires as needed. If Continuity was
measured refer back to flow chart.
Test 7 – Check Field Boost
Procedure
Set DMM to measure DC voltage.
1.
Disconnect the six pin connector from the voltage
2.
regulator.
Disconnect connector C1. See
3.
Component Identification
See Figure 4-14. Disconnect wire 16 from the
4.
starter contactor relay (SCR). This will prevent the
unit from cranking when placed in the START
position.
Figure 4-14. Starter Contactor Relay
See Figure 4-15.
5.
a. Connect the positive meter test lead to wire 4 at
diode D1. Wire 4 is soldered to the diode.
b. Connect the negative meter test lead to the
ground terminal.
14
14
4
4
Figure 4-15. Testing Field Boost
Set the start-run-stop switch (SW1) to START and
6.
measure the DC voltage.
a. Approximately 12 VDC should be measured.
Connect the six pin connector to the voltage
7.
regulator.
40
Control Panel
for connector location.
004606
R1
D2
004607
Connect the C1 connector.
8.
Connect wire 16 to the starter contactor relay.
9.
Results
If 12 VDC was measured in step 6 the field boost
1.
circuit is working. Refer back to the flow chart.
If field boost voltage was not measured refer back
2.
to the flow chart.
Test 8 – Diode/Resistor
Procedure
Set DMM to the diode test range.
1.
Disconnect the six pin connector from the voltage
2.
regulator.
Disconnect connector C1. See
3.
Component Identification
Disconnect both wires from resistor R1.
4.
See Figure 4-16.
5.
a. Connect the positive meter test lead to the top
terminal of diode D1.
a. Connect the negative meter test lead to the
bottom of the diode.
a. Infinity or "Open" should be measured.
14
WIRE 14
REMOVED
14
R1
4
4
Figure 4-16. Diode Test Step 5
See Figure 4-17.
6.
a. Connect the positive meter test lead to the
bottom terminal of diode D1.
b. Connect the negative meter test lead to the top
of the diode.
c. Approximately 0.5 volts should be measured.
Set DMM to measure resistance.
7.
a. Connect one meter test lead to the top terminal
of diode D1.
Control Panel
for connector location.
OL
D2
004608
Diagnostic Repair Manual