TM 11-6625-1683-15
section may become apparent while operating
exposed. Use every precaution to avoid the
from the ac powerline only, from a 6-volt dc
hazard of a severe shock.
source only, o r f r o m e i t h e r t y p e o f p o w e r
supply.
6-4. Checking INPUT POWER Circuits
Symptoms, causes, and corrective measures
F a u l t y functioning of the INPUT POWER
are given in the chart below.
Probable trouble
Correction
Symptom
Operating from ac powerline, INPUT
POWER switch S1 at AC ON:
a. Replace indicator light DS1.
a. Indicator light DS1 defective .
Red AC ON indicator DS1 light
does not go on.
b. Interlock switch S28 not closed .
b. Apply sufficient pressure to close
switch.
c. No power on ac supply line . . .
c. Check line fuses or control switch.
d. With INPUT POWER switch at
d. Interlock switch S28 defective .
OFF and interlock switch S28
closed, using low ohms range
of multimetir, check continuity
across contact of interlock
switch section S28B. Should
indicate closed circuit; other-
wise replace interlock switch
S28.
e. With the power cable disconnected
e. INPUT POWER switch S1 de-
from the powerline and INPUT
fective.
POWER switch S1 at AC ON,
check continuity across switch
contacts. Closed circuit should
be indicated; otherwise, replace
switch S 1.
Operating from 6-volt dc power source,
INPUT POWER switch at DC ON:
a. Replace indicator light DS2.
a. Indicator light DS2 defective ._
Clear DC ON indicator DS2 light
does not go on.
b. Replace with charged battery.
b. Battery charge low -----------
c. Apply sufficient pressure to close
c. Interlock switch S28 not closed_
switch S28.
d. With INPUT POWER switch at
d. Interlock switch S28 defective -
OFF and interlock switch S28
closed, using low ohms range
of multimeter, check continuity
across contacts of interlock
switch section S28A. Should
indicate closed circuit; other
wise, replace switch S28.
e. With 6-volt power source discon-
e. INPUT POWER switch S1 de-
nected and INPUT POWER
fective.
switch S1 at DC ON, check con-
tinuity across switch contacts
S1C8 to S1C9 and SID11 to
S1D12. Closed circuit should be
indicated; otherwise, replace
switch S1.
6-3
AGO 7918A
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