TM 11-5805-424-15/NAVSHIPS 0967-220-9010/TO 31W2-2G-41
c. Troubleshooting Chart-Continued
Item
Symptom
Probable trouble
Corrective measure
No.
12
Loss-of-transmit-carrier alarm
f. Defective bistable FFE-1 or OR
f. Check output voltage at test jack J2
activated with INPUT
gate GOA-6 on assembly A3 (fig.
of PC 80034140 (fig. 6-4). If out-
SELECT switch in any
8-8).
put is positive (ground), trouble-
position-Continued
shoot FFE-1 (para 6-5) and GOA-
6 (para 6-6d); replace defective
components.
13
No-transition send alarm acti-
Defective alarm circuit on assembly
Check for ground at TP1 of PC
vated; send output normal.
A12 (fig. 8-17); defective delay
80034060 (fig. 6-13). If not present,
driver Q5, Q6, Q7.
check AND gates GAS-1 and GAS-2
- 15 volts at TP2; if present, check
delay driver components (fig. 8-7
at TP3. If not present, check ca-
pacitor C4, resistor R17, and diode
CR5; replace defective components.
If positive voltage not present at
TP3, check 5-second delay transistor
Q8 circuit components; replace de-
fective parts. Check for ground at
TP5. If not present, troubleshoot
amplifier IN-3 (para 6-7a).
14
ALARM indicator lamp does
a. Defective OR gate GOB-1 on as-
a. Troubleshoot OR gate (par a 6-6d);
not light when alarm con-
sembly A12 (fig. 8-17).
replace defective components
dition exists.
b. Defective amplifier IN-5 (fig. 8-17)
replace defective components
15
Send data is not transmitted
a. Defective output amplifier Q1, Q2,
a. Troubleshoot amplifier (see 12e(6)
by MD-674(P)/G; no
Q3 on assembly A6 (fig. 8-11).
above).
alarms are activated.
resistances (fig. 6-42); replace, if
defective.
c. Defective OUTPUT switch S7.
if defective (fig. 8-28).
d. Defective diode CR12 or CR13 on
assembly A6 (fig. 8-11).
defective components.
16
Receive data not available at
a. Defective 128 divider-A countdown Check
a. for output at pin F of PC
output of MD-674(P)/G;
module (fig. 8-7).
80034100 (fig. 6-3). If not
no bit-timing signals avail-
present, check amplifier IN-21
able for either type of clock
oscillator operation.
output square wave at test jack
J2, if not present, troubleshoot
countdown chain (FFC-16
through FFC-22, para 6-5).
b. Defective BAUD RATE switch S2-. Check
b. switch; replace, if defective
c. Defective countdown circuit on
c. Check for output square wave at
VCO module assembly A1 (fig.
test jack J2 on PC 80034090 (fig.
6-2). If not present, troubleshoot
countdown circuit (FFC-10,
FFC-11, FFC-12, para 6-5); re-
place defective components.
d. Defective amplifier IN-15 on as-
sembly A1 (fig. 8-6).
replace defective components
6-46
