socket assembly. The indicator lamp (30-A,
lamp (bulb) counterclockwise and re-
move the lamp (bulb) from the socket
tion when using the circuit for testing purposes.
assembly.
The remaining indicator lamps (31, 34, and 35,
(2) Indicator lamps (of the battery circuit
selector instrument panel (41, fig. 16).
i n d i c a t e whether the respective circuits which
Unscrew each lamp (bulb) from the
they are connected with are receiving the nec-
socket assembly.
essary current to function properly.
c. Inspection.
170. Maintenance
(1) Inspect each lamp (bulb) base for cor-
roded condition.
a. General. Organizational maintenance is
authorized to remove and replace the indicator
(2) Check the continuity of each bulb us-
lamps (30-A, 31, 34, 41, and 45, fig. 16).
ing a multimeter.
b. Removal.
d. Installation. Install a serviceable lamp
(1) Indicator lamps (30-A, 31, 34, and 45,
(bulb) in each socket assembly. Install the tor-
f i g . 16). U n s c r e w t h e t o r p e d o l e n s
pedo lens over the indicator lamps (30-A, 31,
from the socket assembly and turn the
34, and 45, fig. 16).
MERCURY SWITCH GROUP
Section VIl.
off the stop button (33-C, fig. 16) and depress
171. Description
the start button (33-A, fig. 16). Determine
The mercury switch (fig. 63) contains two
whether the mercury switch functions by cov-
electrical leads and a small amount of mercury
e r i n g the air intake or air exhaust (fig. 10).
i n a glass enclosure. The two leads are con-
The test stand should stop, then when the cover
nected to the test stand circuitry and the switch
is removed and the drive control (33) is reset
is either closed or open, depending upon
by depressing the start button (33-A), the test
w h e t h e r or not the mercury is contacting the
stand should start again.
e n d of the enclosure to which both leads are
a t t a c h e d . The leads are also connected to the
circuitry of the blower assembly which cools the
(1) Remove the screws securing the meter
load bank within the test stand by expelling the
panel and main control panel in place
heat out through the air exhaust (fig. 10) of the
and lift the panels up and outward to
t e s t stand. The switch is mounted on an air
the length of the nylon cord supports,
trip plate in the air intake duct and the mercury
using the lift handles (fig. 16).
flow direction is controlled by the angle in which
(2) U n s c r e w t h e t w o p a n - h e a d m a c h i n e
t h e switch is placed. Through this action the
s c r e w s and remove the leads of the
t e s t stand operation is stopped when there is
mercury switch from the terminal
an obstruction in the air intake (fig. 10) of the
block. Pull the mercury switch out of
test stand preventing the heat expelled from the
the retaining clip.
test stand load bank to cause overheating and
c o n s e q u e n t l y damaging the load bank and/or
s w i t c h for breaks, chipped glass, cracks, and
the components of the test stand.
frayed, burned, hard and brittle leads.
172. Maintenance
a. General. Organizational maintenance is
( 1 ) Insert the mercury switch in the re-
l i m i t e d to such removal and installation re-
taining clip, Position the leads of the
quired to replace the mercury switch.
switch on the terminal block and se-
b. Test and Adjustment. Operate the test
cure each lead with a No. 6-32 x
stand by sliding the safety clip (33-B, fig. 16)
pan-head machine screw.
