TM 11-6625-2616-14
Section II. INITIAL ADJUSTMENT OF EQUIPMENT
the connector nearest the SIG L plug;
i.e., the tab sticks out to the left of the
Before using Digital Voltmeter AN/GSM-64A
operator when the connector is properly
for routine operation, perfom the procedure
installed.
outlined in paragaph 2-5. These procedures
should always be performed prior to equipment
d. Insert blue plug adjacent to connector into
use after extensive shipment, a long period of
GUARD input jack.
storage, or a drastic change in temperature en-
e. Connect the three clips of the test lead set
vironment.
together. They are covered with red, black, and
blue protective boots.
2-5. Zeroing the Readout
CAUTION
f. Be sure that the VDC and AUTO RNG
Be sure to follow instruction set forth
pushbutton switches are in the "in" position.
in paragaph 2-3c before connecting
g. The instrument readout should display
power cord to ac outlet. Failure to do so
00.0000. If it does not, adjust the ZA potentio-
may cause the fuse to blow and dam-
meter by inserting a small screwdriver in the
age to the transformer.
opening directly underneath the VDC pushbutton
a. Plug the power cord connector into the
switch and turning the adjustment screw until
selected ac outlet.
the readout transfers from 00.0000 to +00.0001;
observe the angle of the screwdriver blade. Back
b. Depress PWR ON pushbutton switch. Al-
off the adjustment until the readout transfers
low 30 minutes for instrument warmup.
from 00.0000 to -00.0001; observe the angle
c. Plug connector of test lead set (P/N 34-
of the screwdriver blade. Now place the adjust-
65) into SIG H and SIG L input jacks.
ment halfway between these two settings. The
AN/GSM-64A is now ready to make measure-
NOTE
ments accurately, conveniently, and quickly.
A small polarity tab sticks out from
