Kohler COM7.5, Service Manual

Page: 46 / 64

TP-6120 5/02 36 Section 5 Controller Operation and Test
5.3.4 Ignition Circuits
Move the generator set master switch to the START
position. If the engine cranks but does not start, check
for spark at the spark plugs. Refer to the Engine Service
Manual for ignition system service information. The
COM7.5 engine uses a capacitive discharge ignition
system.
5.4 Control Board Replacement
NOTICE
Electrostatic discharge damage. Electrostatic discharge
(ESD) damages electronic circuit boards. Prevent
electrostatic discharge damage by wearing an approved
grounding wrist strap when handling electronic circuit boards
or integrated circuits. An approved grounding wrist strap
provides a high resistance (about 1 megohm),
not a direct
short , to ground .
If the controller tests in this section or the
troubleshooting procedures in Section 3 indicate that
the control board needs to be replaced, follow these
guidelines:
D
Keep the new board in its protective wrapping until
installation.
D
Wear a grounding strap while handling the circuit
board to prevent damage to the circuit board
components.
D
Check that all plug connections are secure.
D
Calibrate the new control board after installation.
Control Board Replacement Procedure
1. Move the system controller switch to the STOP or
OFF position.
2. Move the generator set master switch to the STOP
position. (The switch will return to the center
position when released.)
3. Disconnect power to the battery charger, if
equipped.
4. Disconnect the generator set engine starting
battery, negative (--) lead first.
5. Disconnect the three (3) wiring harness connectors
from the control board.
6. Carefully remove the board from its mounting.
7. Install the new control board.
8. Reconnect the three wiring harness connectors.
9. Reconnect power to the generator set engine
starting battery, negative (--) lead last.
10. Reconnect power to the battery charger, if
equipped.
11. Use the following procedure to calibrate the board.
Note: The new control board must be calibrated
after installation.
Calibration Procedure
1. Connect a voltmeter to the DC output terminals of
the voltage rectifier. (See the wiring diagram in
Section 7.)
2. Turn R32 on the circuit board fully clockwise. See
Figure 5-4.
3. Start the generator set with no load.
4. Adjust R32 to obtain the voltage output shown in
Figure 5-5.
GM22402
6
1
1. Common fault indicator LED
2. P1
3. Fuse
4. P2
5. Voltage adjustment potentiometer R32
6. Generator set master switch
7. P3
4 2 3 7 5
Figure 5-4 Generator Set Controls
Generator Set Model Measured Output Voltage, VDC
48 Volt 52
96 Volt 104
Figure 5-5 Output Voltages, VDC