Fluke 87 V/AN, Руководство по обслуживанию

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Digital Multimeter
Troubleshooting
19
current to the beeper and ensure adequate loudness. R108 allows for limiting beeper
current if necessary due to future component changes. R44 in parallel with R47 & C11
set the frequency of the beeper oscillator (note that the junction of R44, R47 & C11
operates at voltages beyond the power supply values). The remaining two U5 inverters
are used in series to form the non-inverting buffer portion of the oscillator.
Troubleshooting
Refer to the “Theory of Operation” and “Schematics” sections to assist in troubleshooting the
Meter.
Restoration Actions
Refer to “Performance Tests”.
Basic Maintenance
XW
Warning
To avoid possible electric shock or personal injury:
•
Remove the test leads and any input signals before opening
the case or replacing the battery or fuses.
•
Repairs or servicing covered in this manual should be
performed only by qualified personnel.
Cleaning the Meter
XW
Warning
To avoid possible electric shock, personal injury, or damage to
the meter, never allow water inside the case.
W
Caution
To avoid damaging the Meter, never apply abrasives, solvents,
aromatic hydrocarbons, chlorinated solvents, or methanol-
based fluids to the Meter.
Periodically wipe the Meter case with Fluke “MeterCleaner” or a damp cloth and mild
detergent.
Dirt or moisture in the
A
or
mA
µ
A
input terminals can affect readings and can falsely
activate the Input Alert feature without the test leads being inserted. Such contamination
may be dislodged by turning the Meter over and, with all test leads removed, gently
tapping on the case.
Thoroughly clean the terminals as follows:
1. Turn the Meter off and remove all test leads.
2. Soak a clean swab with isopropyl alcohol and work the swab around in each input
terminal to remove contaminates.