Fluke 78 - Page 29

Typical Testing Applications
17
1
FUSED
10A
30V
°C°F
300V
30V
RPM
+
COM
V
CAT
COM
RPM
2
1
Hz
MIN / MAX
PRESS
OFF
A
°C°F
HzV
Hz
V
78
AUTOMOTIVE METER
1 SEC
2 SEC
COM
34
DC
V
2
V
1
3
1
2
4
4
5
Press for
2 seconds
RECTIFIER BRIDGE
DIODE CONTACTS
GROUND
BLACK
Insert the test leads as shown.
Turn the rotary switch to diode test.
Press the pushbutton for 2 seconds to toggle to the diode test function.
Touch the red test probe to a diode contact and touch the black to ground.
Typical voltage drop is 0.5-0.8 V and causes the meter to beep.
(Some diodes may drop 0.3 V.)
Reverse the probes. If the diode is:
Good -- the display shows OL.
Shorted -- the display shows near 0 in both directions.
Open -- the display shows OL in both directions.
Repeat steps 4 and 5 for the other diodes.
1
2
3
4
5
6
mt06f.eps
Figure 6. Testing Diodes in Alternator Rectifier Bridge