TM 11-5805-424-15/NAVSHIPS 0967-220-9010/TO 31W2-2G-41
c. Troubleshooting Chart-Continued
Item
Symptom
Probable trouble
Corrective measure
No.
21
Receive carrier alarm not acti-
b. Defective level threshold circuit
b. Check REC CARRIER ALARM
vated when receive input
Q3-Q6.
THRESHOLD resistor 1A1R11
data is removed-Con.
(fig. 8-28); make voltage and
resistance measurements of Q3-
Q6 (fig. 6-36); replace defective
components (fig. 6-10).
c. Defective amplitude detector
c. Check for negative voltage at TP3
circuit Q7, Q8, Q9.
voltage and resistance measure-
ments of transistors Q7, Q8, and
Q9; (fig. 6-36) replace defective
components (fig. 6-10).
d. Defective amplifier IN-10 .
d. Check for - 15 volts at the junction
of diodes CR7 and CR8 on PC
80034050 (fig. 6-10); if not pres-
ent, check amplifier IN-10 (para
6-6a).
e. Defective OR gate GOC-1
e. Check OR gate (para -6d); replace
defective components (fig. 6-10).
f. Defective amplifier IN-9
f. Check amplifier (para 6-7a); re-
place defective components
g. Defective 2-econd delay circuit
g. Check for ground at TP4 on PC
Q11, Q12.
80034050 (fig. 6-10). If not pres-
ent, check transistor Q11, ca-
pacitor C9, diode CR4, and
resistor R34 (fig. 6-10); replace
defective components. If present,
check for +6 volts at test, jack
J4 on PC 80034050; if not present,
check transistor Q12 circuitry
components.
22
No receive data output
a. Defective first and second input
a. Troubleshoot first and second input
available; receive carrier
amplifier Q1, Q2, Q16 on
amplifier Q1, Q2, Q16 circuitry
alarm and no-transition
assembly A9 (fig. 8-14).
receive alarm are activated;
components (fig. 6-10).
all bit-timing signals are
b. Defective EQUALIZER switch S1
b. Replace switch (if used); replace if
normal.
defective (fig. 6-44 or 6-45).
c. Defective receive filter FL1 on
c. Replace receive filter FL1 (fig. 2-6).
MX-73(*)/G (fig. 2-6).
6-50
