Temperature Gauge - Toro Groundsmaster 4100-D Service Manual

Temperature Gauge

The temperature gauge can be tested using a new
gauge as a substitute or with the use of a DC voltage
source and a variable resistance box.
Testing
CAUTION
Make sure the voltage source is turned OFF be-
fore connecting variable resistance to the elec-
trical circuit to avoid electrical shock and to pre-
vent damaging the gauge.
1. Connect temperature gauge to the variable resis-
tance and DC voltage source (Fig. 40).
NOTE: When reading the gauge test point, there are
two white dots on the gauge face below the edge of the
glass cover for each test point. For each variable resist-
ance setting, the needle must be pointed between the
two white dots.
2. Take test point readings (Fig. 41).
IMPORTANT: Allow circuit to warm up for at least 5
minutes before taking test readings.
A. Set variable resistance to 71 ohms. Apply a 14 +
0.01 VDC to the circuit. The needle should point to
the middle of the green area (80
B. Set variable resistance to 38 ohms. The needle
should point between the green and red area
o
(105 C).
3. Turn off the voltage source. Disconnect voltage
source, gauge, and variable resistance.
Electrical System
o
C).
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VARIABLE
RESISTANCE
14 VDC + 0.01 VDC
Figure 40
Figure 41
1. Middle position
2. High temp. position
+
−
1
2
3
3. Edge of glass cover
Groundsmaster 4100−D