TM 55-4920-221-14
with two screws (75) and nuts (73).
(4) Remove other binding posts in a similar
manner.
(4) Connect leads to relay terminals.
b. Cleaning and Inspection.
131. DC AMMETER TERMINAL SELECTOR SWITCH.
a. Removal.
(1) Clean parts with dry cleaning solvent P-D-
680 and dry thoroughly.
(1) Tag and disconnect leads from terminals
of dc ammeter terminal selector switch (14, figure 8).
(2) Inspect thumb knobs and binding posts for
cracks, breaks, and damaged threads.
(2) Loosen setscrew and remove knob (11)
from extension shaft (12).
(3) Inspect insulating washers for cracks,
breaks, and spongy or deteriorated condition.
(3) Remove assembled dc ammeter terminal
selector switch (14) from rear of control panel by
c. Installation.
removing two nuts (17) and screws (16).
(1) Install lug clearance washer (30) and
(4) Remove coupling from shaft of terminal
thumb knob on binding post (32).
selector by removing extension shaft from coupling (13).
(2) Install two insulating washers (34), and
(5) Remove bracket (15) from selector by
binding post (30) in control panel.
removing special nut.
(3) Install bus bar (27) and shunt (10) as
b. Cleaning, Inspection, and Repair.
described in paragraph 128c.
(1) Clean parts with a clean cloth dampened
(4) Install other binding posts in a similar
with dry cleaning solvent, P-D-80 and dry thoroughly.
manner.
(2) Inspect dc ammeter terminal selector
130. RELAYS.
switch for cracked or damaged case, weak or broken
spring, sticking or binding contacts, and damaged
a. Removal.
terminals.
(1) Tag and disconnect leads from terminals
(3) Inspect hardware for worn or damaged
on relays (72 and 78, figure 12).
threads.
(2) Remove bracket and relays (72 and 78)
(4) Repair damaged threads by chasing, if
by removing two screws (75) and nuts (73) securing
practical.
bracket (74) to the control panel.
c. Installation.
(3) Remove relay (78) from bracket (74) by
removing two screws (76) and lockwashers (77).
(1) Position bracket (15) on rear dc ammeter
terminal selector switch (14) and secure with special nut.
(4) Remove relay (70) in a similar manner.
(2) Install extension shaft (12) in one end of
b. Cleaning, Inspection, and Repair.
the coupling (13) and install opposite end of the coupling
(1) Wash hardware in dry cleaning solvent P-
on shaft of ammeter terminal selector.
D-680.
(3) Position assembled bracket and selector
(2) Wipe electrical parts with a clean, lintfree
in control panel and secure with two screws (16) and
cloth moistened in dry cleaning solvent PD-680 and dry
nuts (17).
thoroughly.
(4) Place knob (11) on extension shaft (12)
(3) Inspect relay contacts for pitted or burned
and secure with setscrew.
condition.
(5) Connect leads to terminals of dc ammeter
(4) Clean pitted contacts with a burnishing
terminal selector.
tool. Replace if contacts are burned.
(5) Inspect coil for brittle, cracked or
132. HIGH-LOW AND FAN OFF-ON SWITCHES.
deteriorated insulation, and damaged leads or windings.
a. Removal.
(6) Inspect threaded parts for worn or
(1) Tag and disconnect leads from terminals
damaged condition.
of high-low switch (18, figure 8).
c. Installation.
(2) Remove switch from rear of control panel
(1) Attach relay (78) on bracket (74) with two
by removing special hex nut securing switch to front of
screws (76) and lockwashers (77).
control panel.
(2) Install relay (72) in a similar manner.
(3) Remove fan off-on switch (32) in a similar
(3) Attach bracket on side of control panel
manner.
46
