ARMY TM 9-6115-604-12
NAVY NAVFAC P 8 633-12
4-110. PHASE SEQUENCE INDICATOR LIGHTS (1 2 3, 3 2 1) DS112 AND DS113 (14, Figure 2-2). These lights indi-
cate the phase sequence of generator G1 and the bus.
Dangerous voltage levels may be present within upper cabinet B. Follow all
applicable safety precautions outlined In Chapter 1, Section III , of this manual.
a.
Test. Push PHASE SEQ. LAMP TEST button (16, Figure 2-2). If a lamp fails to light when expected, proceed
as follows:
(1) See Figure 4-72. Set multimeter at 1 20V AC scale and check for presence of power at lamp holder (3)
terminals. If power is not present when lamp should light, use wiring diagram FO-1 to trace back through
circuit until defective wire or item is found. Repair or replace as required.
(2) If power exists at lamp holder (3) terminals, replace lamp (2) with a known good lamp. Refer to step c,
below.
(3) If known good lamp (2) does not light, replace lamp holder (3). Refer to step c, below.
(4) Using a multimeter set to RX100K scale, check the resistance of the resistors at the back of the lamp
holders. Resistance should be 27,000 ohms 10%.
(5) Replace resistors which do not meet these specifications.
b.
Remove. See Figure 4-72.
(1) Remove clear lens (1) covering lamp (2). Remove lamp (2).
(2) Disconnect wires and resistor by unsoldering in accordance with MIL-STD-454H Standard General
Requirements for Electronic Equipment from lamp holder (3)
(3) Remove lamp holder (3) from panel by removing attaching hardware.
c
Repair . Repair consists of replacing defective lampholders (3) and lamps (2). Refer to steps b and d.
d
Install. See Figure 4-72
(1) Install lamp holder (3) In panel Secure with attaching hardware
(2) Connect wiring and resistor by soldering In accordance with MIL-STD-454H Standard General Requirements
for Electronic Equipment to lamp holder (3) as required
(3) Install lamp (2)
(4) Install clear lens (1)
4-111. FREQ ADJ RHEOSTAT R102 (8, Figure 2-2). FREQ ADJ rheostat R102 is used to manually adjust the
frequency level of the output of generator G1.
a.
Test.
(1) Remove wire from terminal 3 of FREQ ADJ rheostat R102
(2) Rotate knob fully counterclockwise
(3) Set a multimeter to RX100 scale and check resistance across terminals 1 and 2 Maximum resistance should
be 10 ohms
(4) Reset multimeter to RX10K. While observing the multimeter Indications slowly rotate knob In a clockwise
direction Meter resistance indication should Increase smoothly, with no erratic jumps at any point in travel.
(5) When knob (wiper arm-terminal 2) Is In the fully clockwise stop position, total resistance indication should be
5000 ± 500 ohms.
(6) Connect wire removed from terminal 3.
4-176
