TM 11-6625-2616-14
OPERATION
Section I. OPERATOR'S CONTROLS, INDICATORS, AND INPUT JACKS
that the power-selection switch on the rear of the
3-1. General
instrument is in the 230 position. If this pre-
This section lists, illustrates and describes the
various controls, indicators, and input jacks pro-
caution is not observed, the fuse will blow and
vialed for the operation of the digital voltmeter.
the power transformer may be damaged.
These items are listed, with their functions in
scribed in section II of this chapter.
3-2. Damage from Improper Settings
Input Jacks
If a 230-volt power source is to be used, be sure
Function
Incandescent bulbs behind mask indicate polarity of dc voltage applied to SIG H
terminal with respect to SIG L terminal in vdc and ratio modes.
Readout tubes ------------------
Gas discharge display tubes which provide the readout in decimal form, There are
six plug-in tubes, each containing the numerals 0 through 9 and a decimal point.
Places the instrument in the ac voltage measurement mode if an AC/DC Converter
VAC pushbutton switch ........
accessory is installed (para 1-4b).
VDC pushbutton switch . . . . . . . . .
Places the instrument in the dc voltage measurement mode.
Places the instrument in the ratio measurement mode. The reading displayed is
R(%) pushbutton switch . . . . . . . .
the ratio of the input voltage to the reference voltage in percent.
ZA potentiometers . . . . . . . . . . . . . .
Permits adjusting the readout to 00.0000 when input leads are shorted together.
EXT REF VDC toggle switch . . .
Selects external reference range of instrument.
Applies vac line power to the instrument.
PWR ON pushbutton switch ----
AUTO RNG pushbutton switch ..
Selects automatic ranging mode of operation.
Changes range of instrument if AUTO RNG switch is in the "out" position.
RNG CHNG Pushbutton switch ..
Front and rear jacks connect to instrument signal input.
SIG H input jack . . . . . . . . . . . . . .
Front and rear jacks connect to instrument signal common.
SIG L input jack . . . . . . . . . . . ...
Front and rear jacks connect to inner guard shield,
GUARD input jack -------------
EXT REF input jack . . . . . . . . . . .
Connection for external reference voltage input.
Incandescent bulb behind mask flashes symbol when input voltage exceeds full
Overload indicator --------------
scale capability of range selected if in manual range, or overall instrument
capability if in AUTO RNG mode.
Power-selection slide-switch ....
Permits operation from either 115 vac or 230 vac input power source.
