Model 787
Calibration Manual
10
Checking and Replacing Fuses
WWarning
To avoid electric shock or personal injury, remove the test leads and
any input signals before replacing a fuse. Make sure that the battery
door and case are closed and secured before operating the
ProcessMeter.
To avoid injury or damage to the ProcessMeter, use ONLY specified
replacement fuses with the amperage, voltage, interrupt and speed
ratings shown in Table 13.
Both current input terminals are fused with a separate 440 mA fuse.
To determine if a fuse is blown:
1. Turn the rotary switch to mA A L.
2. Plug the black test lead into COM, and the red test lead into DA.
3. Using an ohmmeter, check the resistance between the ProcessMeter test leads.
If the resistance is about 1Ω, the fuse is good. An open means the fuse is blown.
4. Move red test lead to
FmA.
5. Using an ohmmeter, check the resistance between the ProcessMeter test leads.
If the resistance is about 14 Ω, the fuse is good. An open means the fuse is blown.
To replace a fuse, refer to Figure 2 and do the following:
1. Turn the rotary switch to OFF, remove the test leads from the terminals, and hold the
ProcessMeter face down.
2. Remove the battery door by using a flat-blade screwdriver to turn the battery door
screws 1/4-turn counterclockwise.
3. Remove the three Phillips-head screws from the case bottom and turn the case over.
4. Gently lift the input terminal-end of the case top to separate the two halves of the
case.
5. Remove the fuse by gently prying one end loose, then sliding the fuse out of its
bracket.
6. Replace the fuse only with a 440 mA 1000 V fast-blow fuse. (Fluke PN 943121.)
Both fuses are the same type.
7. Verify that the rotary switch and the circuit board switch are in the
OFF position.
8. Place the case top on the case bottom, ensuring that the gasket is properly seated and
the case halves snap together above the LCD end. (See Figure 2.)
9. Reinsert the three case bottom screws and the battery door.
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