TM 11-6625-1702-35
b. Troubleshooting Chart.
Item
Symptom
Probable trouble
Correction
Test procedure
No.
1 Dc meter scale test a. Meter indication of 28- a. R2 or M1 defective ---- a. Replace defective com-
ponent.
volt dc input high.
tive or there is a
continuity checks ( para
volt dc input low.
short in the associated
fect. Replace defective
circuits.
component.
C. Perform
resistance and
c. Meter indication zero --- c. F1, R2, M1, or S3 defec-
tive or there is an
continuity checks to lo-
open circuit in the 28-
cate the defect. Replace
volt dc line.
defective component.
2 Millivolt source test a. Voltage at MV OUT- a. CR1 defective ---------- a. Replace CR1.
PUT terminals very
unstable.
to locate defective com-
defective.
zero.
ponents. Replace defec-
tive component.
C. MV OUTPUT voltage
c. C1 or M1 defective ____ c. Replace defective compo-
nent.
correct but meter in-
dication is excessively
high or low.
I N D I C A T O R a. DS1, Q3, Q2, or R12 a. Check TUNE INDICA-
3 TUNE INDICA- a. T U N E
TOR DS1. Check re-
defective.
TOR
function
does not light.
sistance of R12. Per-
test (para 4-7).
form voltage and re-
sistance measurements
(para 2-7c) on Q3 and
Q2. Replace defective
component.
b. TUNE
INDICATOR b. CR2, CR3, CR4, Q2, b. Perform resistance checks
and voltage and resist-
Q3, R9, R10, R11,
does not extinguish
ance measurements as
R12, or C2 defective.
when coupler is con-
required to isolate de-
nected and MV AD-
fective component. Re-
JUST control is fully
place defective com-
counterclockwise.
ponent.
c. TUNE
INDICATOR c. CR2, C2, Q2 or Q3 de- c. Perform voltage and re-
sistance measurements
fective.
does not illuminate
as required to isolate
brightly.
malfunction. Replace de-
fective component.
d. Repetition rate too slow d. Q1 defective ---------- d. Replace Q1.
(greater than 20 ms)
when TUNE INDI-
CATOR reaches full
brilliance.
4 Coupler test (para a. Coupler does not cycle __ a. Z1, S1, or associated a. Perform continuity checks
on wiring, connectors,
connectors or wiring
and S1. Repair or re-
defective.
place as required. If no
defects are found in S1
or the associated wir-
ing, replace Z1.
2-5
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