Mastech M839b Instruction Manual

POCKET-SIZED

DIGITAL MULTIMETER

OPERATOR’S
INSTRUCTION MANUAL

F250mA250V

SAFETY INFORMATION

The meter has been designed according to IEC1010 concerning
electronic measuring instruments with an overvoltage category (CATII)
and pollution 2.
Follow all safety and operating instructions to ensure the meter is used
safely and is kept in good condition.
Full compliance with safety standards can be guaranteed only with test
leads supplied. If necessary, they must be replaced with the type specified
in this manual.

DURING USE

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Never exceed the protection limit indicated in the specifications for
each range of measurement.
When the meter is linked to measurement circuit, be careful not to
touch unused terminals.
Never use the meter to measure voltages that might exceed 600V
above earth groud in category II installations.
Always be careful when working with voltages above 60V dc or
30V ac rms. Keep fingers behind the probe barriers while
measuring.
Before attempting to insert transistors for testing, always be sure
that test leads have been disconnected from any measurement
circuits.
Components should not be connected to the hFE socket when
making voltage measurements with test leads.
Do not perform resistance measurements on live circuits.

SAFETY SYMBOLS

Important safety information, refer to the instruction manual.

Dangerous voltage may be present.
Earth ground.
Indicates compliance with requirements for double insulation
Fuse must be replaced with ratings specified in the

manual.

MAINTENANCE

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Before opening the case, always disconnect test leads from all
energized circuits.
For continuous protection against fire, replace fuse only with
ratings: F 250mA/250V (Quick Acting).