Fluke 12B, Руководство по обслуживанию

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12B/18/7 Series
Service Manual
3-10
+
_
9V
BATTERY
+
Clip to Base Contacts
Adjust R4 for 3.997-4.003V DC
Input Receptacles
+
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Figure 3-4. Calibration Adjustment
Calibration Adjustments for Models 7-300 and 7-600
To ensure that the meter performs to specifications, make calibration adjustments
annually using the following procedure:
1. Set the calibrator for 0V dc. Switch the meter ON.
2. Connect the calibrator to the [+] and COM jacks on the meter. Defeat the 50
Ω
divider on the calibrator (if any).
3. Apply an input of 3.500V dc
±
0.25%. Wait at least 3 seconds.
4. Apply an input of 3.75V dc
±
0.25%. Within 5 seconds the meter should display a
reading between 3.747 and 3.753V dc. If it does not, adjust R4 as described below.
To adjust R4, proceed as follows:
1. Remove any input signal to the meter.
2. Remove the four screws on the back and separate the case bottom from the case top.
Notice that when you do so, the battery remains in the case bottom and power to the
meter is disconnected.
3. Observing the correct polarity, connect a known good 9V battery to the battery
contacts using easy-hook jumpers or alligator clip leads. Refer to Figure 3-4.
Note
To avoid stretching or bending the battery contacts, connect the leads to
the base of the contacts, as shown in Figure 3-4.
4. Set the calibrator for 0V dc. Turn the meter ON.
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