Specifications

(2)
chart (para 34) and the schematic
30. Test Equipment Required
diagram (fig. 39) to find normal
The following chart lists equipment re-
readings, and compare them with
quired for troubleshooting Test Set, Radio
readings taken.
AN/VRM-1:
Intermittent troubles. In all these
tests, the possibility of intermittent
troubles should not be overlooked.
If present, this type of trouble often
may be made to appear by tapping
or jarring the equipment. Check the
wiring and the connections to the
AN/VRM-l.
Section Il. TROUBLESHOOTING
Caution: Do not attempt removal or replacement of parts
tions given in paragraphs 35 through 40.
31. Checking Dc Supply Circuit for Shorts
(4) Check
before reading the instruc-
to be sure that fuse F7901
-
a. When to Check. Check for short cir-
cuits and clear the trouble whenever ab-
normal symptoms reported from opera-
tional tests indicate possible dc supply
circuit troub1es. (Refer to equipment
performance checklist, TM 11-6625-496-
12.)
b. Conditions for Test. To prepare for
the short-circuit tests, perform the fol-
lowing operations:
(1) Turn the selector switch to A.
(2) Set the ON-OFF switch to ON.
(3) Disconnect CX-7899/VRM-l from
the front panel of the TS-1777/
VRM-1.
is good.
(5) Remove the front panel and chas-
sis assembly from the case (para
36).
c. Measurements. Make the resistance
measurements indicated in the chart be-
low. If abnormal results are obtained,
make the additional isolating checks out-
lined. When the faulty part is found, repair
the trouble before applying power to the
unit.
Note: When measuring resistance, negative volt-
age is applied to the OHMS lead of the ME-26BAJ.
If another type of meter is used, determine the
polarity of the ohmmeter leads before checking the
dc supply circuit for shorts.
32. Test Setup
a. Power Supply Connections. For bench
Remove the front panel and chassis as-
testing power
-
apply PP-2309/U is used
semblies from the case (para 36) and make
in place of a vehicular electrical system
the test setup outlined below.
which is normally used to furnish power
18