TM 11-4625-596-45
b.
Troubleshooting Chart
Action and indication
Possible cause
Correction
Turn power switch 1A4S8 on. POWER
Fuses 1A4F2, 1A4F3 (230-volt input)
Replace fuses. Check power switch to see
ON lamp 1A4DS2 does not light
or 1A4F4, 1A4F5 (115-volt input) are
that correct line voltage is selected.
blown.
Check power cable and connections, If
fuses blow again, remove 1A3A5 and
1A3A6.
a. Check for shorts to ground from
1A3J5-H, -D, and -F. If a short is
found, check 1A3CR2, remove each
printed circuit board until the short
is eliminated. If no short is located,
replace 1A3A5.
b. Check for shorts to ground from
1A3J6-B, -A, -H, and -C. If a
short is found, check 1A3CR1, re-
move each printed circuit board
until the short is eliminated. If no
short is found, replace 1A3A6.
If signal is heard in loudspeaker but
No signal at 1A3J8-U ---------------------- Check continuity between 1A3J8-U,
meter does not read.
1A3R11-1, and 1A3J4-B.
No signal at 1A3J8-V----------------------- Replace 1A38.
No signal at 1A3J8-A----------------------- Check continuity between 1A3J8-V,
1A4S6A-5, and 1A3J8-A.
No signal at 1A3J8-B----------------------- Replace 1A3AS.
No signal at 1A4M-1------------------------ Check continuity between 1A3J8-B,
1A4S6A-8, 1A4S6A-7, 1A4S6M-7,
1A4S6L-5, 1A4S5F-5, and 1A4M1-1.
Signal to 1A4M1-1 but no reading on
Open circuit------------------------------------ Check continuity between 1A4M1-2,
meter.
1A4S5F-2, 1A4S5F-1, 1A4S6L-1,
1A4S6M-4, and 1A3J8-C. With 1A3A8
1A3J8-C to ground. If more than 30
ohms, replace 1A3A8.
METER ADJ button 1A4S6S
No signal at 1A3J8-N------------------------ Check continuity between 1A3S6A-2 and
depressed.
1A3J8-N.
Meter does not deflect when METER
No signal at 1A3J8-M------------------------ Replace1A3A8.
SENSITIVITY control 1A4R14 is
No signal at 1A3J2-S------------------------ Check continuity between 1A3J8-M,
rotated.
1A4S5E-4, 1A4S5D-4, 1A4S5C-4,
1A4S5B-4, 1A4S7B-5, 1A4S7A-5,
1A4S7A-6, and 1A3J2-B.
No signal at 1A3J2-C------------------------ Check continuity between:
a. 1A3J2-J and 1A3R14-1.
b. 1A3J2-L and 1A3R14-2.
c. 1A3R14-3 and ground.
If present, replace 1A3A2.
No signal at1A4MI11------------------------ Check continuity between:
a 1A3J2-C and 1A3R16-1.
b. 1A3R16-2, 1A4S6N-10, 1A4S6E-7,
1A4S6D-7, 1A4S6C-7, 1A4S6B-5,
and 1A4S6A-7.
Signal at 1A4M1-1, no deflection of
Open circuit------------------------------------ Check continuity between 1A4S6S-2,
meter.
1A4S6S-1, 1A3J2-F, and 1A3J8-C.
Fuse 1A3F1 blown---------------------------- Replace 11A3F1 (FIG. 3-3).
R1NGER button 1A4S6C, 1A4S6D,
No 100 volts dc at 1A3A11-1-------------- If 100 volts de at 1A3A11-1, replace
or 1A4S6E, or INSULATION
1A3A11.
If 100 volts dc not at 1A3A11-1, check
depressed.
for presence at 1A3J5-D.
If not at 1A3J5-D, replace 1ASA5.
If 100 volts de at 1A3J5-D, check
continuity between:
a. 1A3J5-D and 1A3XFl-1.
b. 1A3A11-1 and 1A3XF1-2.
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