TM 11-6625-214-12
Table 4-5. Troubleshooting AN/URM-52(*)
Malfunction
Probable cause
Corrective action
a. Blown fuse F301 and/or F302.
Instrument dead; neither indicator;
lights no output.
of fuse indicates trouble within the in-
strument which must be corrected
before normal operation may he
resumed.
b. Poor connection or failure of,
primary source of alternating current. b. Check power connection.
With the MODSELECTOR switch in
Check operation of relay K301 by
the CW position and POWER SET
checking if heaterofV306 lights
control adjusted for normal reading,
approximately 2 minutes after power
DBM/ POWER SET meter fails to
is applied to the instrument
deflect from ZERO SET 2
minute after power is applied
Section IV. MAINTENANCE OF AN/URM-S2(*)
corrosion.
4-8.
Cleaning
Inspect the exteriors of the signal generator and transit
4-10.
Replacement of Indicator Lamps.
case. The exterior surfaces should be clean, free from
a. Turn
the
glass
indicator
jewel
dust, dirt, grease, and fungus.
a. Remove dust and loose dirt with a clean
counterclockwise and pull out to expose the defective
soft cloth.
lamp.
b. Press in on the lamp and turn
WARNING
counterclockwise to unlock.
The fumes of trichloroethane are toxic.
c. Pull the defective lamp out and replace it
Provide thorough ventilation whenever
with a new one (GE No. 47). Push the lamp in and twist
used. DO NOT USE NEAR AN OPEN
it clockwise to lock.
FLAME.
Trichloroethane
is
not
d. Replace the glass indicator jewel.
flammable, but exposure of the fumes to
an open flame or hot metal surface
forms highly toxic phosgene gas.
4-11.
Replacement of Fuses
b. Remove grease, fungus, and ground-in dirt
from the transit case; use a cloth dampened (not wet)
terclockwise, and pull out to expose the defective fuse.
with trichloroethane.
b. Pull the defective fuse out and replace it
c. Remove dust or dirt from plugs and jacks
with a new one (3 amperes for AN/URM-52 and
with a brush.
AN/URM- S2B, 3.2 amperes for AN/URM-52A).
d. Clean the front panel, meter and control
knobs of the signal generator; use a cleaning cloth. If
neces- sary, use mild soap and water to remove dirt.
4-12. Repair of Defective Cables and Cords
Use electrical insulation tape to repair all breaks, cuts,
4-9.
Touchup Pointing Instructions
Remove rust and corrosion from metal surfaces by lightly
CX-3135/U, Power Cable CX337/U, RF Cable CG-
sanding them with fine sandpaper. Brush two thin coats
92D/U, and Video Cord CG-409/U.
of paint on the bare metal to protect It from further
4-4