TM 11-6625-539-14-3
CHAPTER 6
TROUBLESHOOTING AND REPAIR
(d) Inspect for loose or missing screws,
specifically those that fasten the rear parts board
a. General. The first procedure in servicing a
in place.
defective test set is to sectionalize the fault, Sec-
(2) Operational tests. Operational tests fre-
tionalization consists of tracing the fault to a
quently indicate the general location of trouble.
group of circuits concerned with one test function.
In many instances, the test will determine the
Once the defective function is found, isolation
exact nature of the fault. The operator's preven-
to the defective part is accomplished. Trouble-
tive maintenance checks and operational check
shooting is performed by general support and
depot repairmen.
b. Sectionlization. Listed in (1) and (2) be-
test.
low is a group of tests that are arranged to help
(3) Troubleshooting chart and equipment
locate the defect to a faulty component.
required. The meter indications, or lack of meter
indications, and operational checks provide a
(1) Visual inspection. When the test set is
systematic method of localizing trouble to the
brought in for repair, remove the front panel and
faulty circuit. The trouble symptoms listed in the
inspect as follows:
troubleshooting chart (para 62) provide addi-
(a) Check to see that all connections are
tional information for localizing troubles. The
properly seated. Repair or replace any connec-
only test equipment required is Voltmeter, Elec-
tions or leads that are broken or otherwise de-
tronic ME-30(*)/U (TM 11-6625-320-12).
fective.
(b) Check all switches and controls for
NOTE
ease of operation.
Voltmeter, Electronic ME-30(*)/U re-
(c) Remove the access cover to the bat-
p r e s e n t s Voltmeter, Meter ME-30A/U
teries, and check for corrosion and looseness of
and Voltmeters, Electronic ME30B/U
batteries.
and ME30E/U.
Symptom
Probable cause
Corrective measure
Meter pointer does not fall within BAT
Batteries loose or weak. Meter Ml
Check batteries (fig. 6-1). Check meter
position on scale with function switch
defective.
Ml.
on BAT.
Meter pointer does not align (para 7-2)
VR1, R10, R11, or R13 defective . . Check VR1, R10, R11, and R13.
ME-30 ( )/U does not indicate 100 mv
Q1, Q2, Q3, or T1, or associated cir- Check Q1, Q2, Q3, T1, and associated
cuitry defective (fig. 5-6 and 7-1).
Meter pointer does not indicate full
Q4, Q5, Q6, CR1, CR2, CR3, CR4, Check Q4, Q5, Q6, and CR1 through
scale (para 7-3).
or associated circuitry defective.
CR4.
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