TM
55-4920-244-14
(5) Replace defective tubes (para. 4-
(6) Use a decade resistance bridge or
36.)
other precision resistance checker to make sure
all resistors are within tolerance.
(6) Replace resistors not within toler-
ance indicated on body.
NOTE
(7) Replace any capacitors not within
Unsolder one lead of re-
tolerance or showing excessive leakage.
sistor under test to iso-
late from circuit.
(8) Repair broken wiring in cable
harness as follows:
(7) Use a suitable capacitor checker
(a) If slack in wire beyond end
to test all capacitors for leakage and capacity.
of cable permits, bare 1/4 inch of wire at break
(8) Inspect cable harness and all
and install in terminal in place of broken end.
wiring for broken wires and condition of insula-
(b) If insufficient slack is pres-
tion.
ent, splice a suitable length of same size and
(9) Inspect all wiring for shrinking
color wire at break and cover splice with 3/32-
of insulation or other signs of overheating.
or 1/8-iinch plastic tubing or an approved elec-
(10) Inspect electrolytic (polarized)
trical tape. If same color wire is not available,
capacitors for leakage of electrolyte.
use white wiring and color code insulation on
(11) Use an ohmmeter or suitable
terminal end with color(s) of original wire.
continuity checker to test transformer for open
(c) If wiring break is detected
windings, continuity between windings, or conti-
within cable harness and is readily located, re-
nuity between windings and case.
pair as in (b) above. Do not splice more than
e. Repair.
once in any conductor.
(1) Replace any of the printed cir-
(d) If wiring break is detected
cuit boards if any of the following conditions
within cable harness and not readily located, re-
exist:
place wire as outlined in (9) below.
(a) Separation of plies in board
(e) Cover any minor damage to
material.
wiring insulation by covering individual wires
(b) Cracks over 1/8 inch in
with 3-32- or 1/8-inch plastic tubing.
length, or extending into a terminal mounting.
(c) Carbonized paths between
(9) Repair wiring having burnt or
terminals or between terminals and ground.
shrunken insulation as follows:
(d) Loose, separated, or broken
(a) Trace affected wire to its
terminal lugs.
origin. Unclamp and untie cable harness along
(2) Separate all components at cold
entire length of affected wire.
soldered or corroded joints. Clean terminal and
(b) Examine other wires in cable
conductors of all corrosion and excess solder. Tin
harness for heat damage to insulation.
all surfaces to be soldered and remake joint.
(c) Replace entire length of all
damaged wiring, using same size and color wire.
CAUTION
If same color wire is not available, use white
Provide a heat sink on
wiring and color code insulation on both ends
precision resistor leads be-
with color(s) of original wire.
tween body of resistor
(d) Bundle wiring along origi-
and point being soldered
nal path of cable harness and lace in accordance
or tinned to prevent dam-
with instructions contained in TM 55-1500-323-
age from overheating
25 at 1-inch intervals.
when soldering.
(10) Replace potentiometer if erratic
(3) Replace nicked or scored compo-
action is noted as adjusting screw is turned.
nents or components with broken leads. Replace
(11) Replace electrolytic (polarized)
any component showing signs of overheating and
capacitors if swollen or signs of electrolyte leak-
determine cause.
age are noted at seams or terminals.
(4) Replace tube or relay sockets if
damaged or if carbonized paths are found. Re-
(12) Replace relay clamp if defective.
place or tighten missing or loose attaching hard-
(13) Replace transformer if condi-
ware.
tions in
above exist.
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