Onan MicroLite 4000 Series User Manual

9-12
VOLTAGE REGULATOR (VR1) TEST
Confirm that the voltage regulator is faulty before
replacing it. Use a meter with a diode checking func-
tion (Fluke model 73 or equivalent multimeter) to
perform the following tests.
1. Disengage the J4 wiring connector and remove
the voltage regulator (Figure 9-6 on Page
9-8).
2. With the meter set on “Diode Check”, test be-
tween connector terminal pairs: 5-9, 7-9, 10-9,
11-9, 12-9, 10-5, 5-11, 5-12, and 5-3. The posi-
tive (+) meter lead must be connected to the
first terminal of each pair.
3. Replace the voltage regulator if any reading in-
dicates a “short” or “open”, except for pair 10-5,
which should indicate an “open”.
NOTE: “Short” is indicated by zero or a number
very near zero. Meters of different make indicate
“open” differently, read the meter instruction
manual. If in doubt, compare with readings of a
regulator of the same part number that is known
to be good.
4. If the regulator checks “good”, there is a
chance that the regulator could still be bad.
Verify that the connector pins are making good
contact. If voltage regulation problems contin-
ue, replace the voltage regulator with a known
good regulator and recheck operation.
BRUSHES AND SLIP RINGS
This section covers brush replacement and slip ring
service.
Brush Replacement
Follow Generator Disassembly / Base Removal
procedures on Page 9-2 through fan hub assem-
bly removal. Inspect the brushes and brush block
for burn marks or other damage. If the brushes ap-
pear to be in good condition, use a piece of wire
(modified as shown in Figure 9-10) to check for ex-
cessive brush wear (minimum brush length is 0.375
inches [9.5 mm]). Insert the painted end of the wire
through the hole above each brush. Make sure the
wire is resting on the brush and not on the spring. If
the painted part of the wire is not visible, the brush is
excessively worn and must be replaced. Always re-
place the brush springs when installing new
brushes to maintain proper tension on the brushes.
Clean carbon deposits from brushes and slip rings
(see
Slip Ring Service section on Page 9-13). Use
the following procedures to replace the brushes:
G1178-2s
1 IN. (25 MM)
FIGURE 9-10. BRUSH WEAR CHECK
G1179-2s
BRUSH
HOLDER
WIRE
SPRING
BRUSH
FIGURE 9-11. BRUSH REPLACEMENT

Onan MicroLite 4000 Series Specifications

General

Brand	Onan
Model	MicroLite 4000 Series
Category	Portable Generator
Language	English