TM 11-6525-586-45
Probable Trouble
Correction
Symptom
14. cont.
Harmonic generator A6A1Q1, A6A1Q2
Check for harmonic spectrum signal
defective.
at junction of A6A1C5 and A6A1C8.
If absent, check and replace A6A1Q1
or A6A1Q2. Refer to 2-21 and 6-8(3).
Beat Note mixer A6A1CR1 or am-
Check and replace defective part.
plifier A61Q3, A6A1Q4, Q2 or Q7
Refer to figure 6-8.
defective
b. Transistor Voltage Checks
2-6. Isolating Trouble Within a Transistor
NOTE
Stage
When trouble has been localized to a transistor
Transistors or diodes omitted from the following
do not require voltage checks, either because
stage, either through operational checks, or trou-
access requires extensive disassembly or because
bleshooting charts (para 25), isolate the defec-
checks would be meaningless.
tive part by voltage measurements (para 27).
Transistor
Voltage (volts)
Emitter
or
CAUTION
Scope and Type
Anode
Collector
Notes
Q1
2N930
2,6
1.13
1.7
14.8
Before attempting to perform voltage
Q2
2N1613
1.1
2,6
1.8
13.4
measurements review paragraph 2-4.
Q3
.8
11.8
2N930
3,4,5
1.6
Q4
Carefully follow instructions. Careless-
2N1613 11
23
3,4,5
11.8
Q5
2N930
3,4,5
0
0.64
8.8
ness may cause additional troubles in the
Q6
2N930
12.6
23
3,4,5
12.0
equipment and make the troubleshoot-
Q7
2N706 0
3,4,5
1.55
.64
ing job more difficult. Never remove or
13.0
Q8
2N1490
12.0
18.0
connect a transistor with voltage ap-
Q9
2N1490
25
26
48
Q10
2N1893
26
26.5
48
plied to the circuit.
Q11 2N2905 43.5
43
26.5
13
Q12 2N760A 4.4
5
Q13
2N760A
4.4
26.5
5
are wired into the circuit. Every effort should
3,4,5
12.4
1.13
Q14 2N760A
.48
10
3,4,5
Q15
2N1613
1.7
2.5
be made to troubleshoot the equipment without
13.0
Q 1 7 2 N 1 6 1 3 12.4
23.5
physically unsoldering and removing the transis-
A1Q1 2N2857 8.8
23
8.2
1,2
tors.
1,2
6.95
A1Q2 2N2857 .2
.9
16.5
1,2
5.6
A1Q3 2N3866 5.0
b. If all checks fail to indicate a defective part,
3,4,5
11.8
`1.6
A2Q3 2N2219 0.8
3,4,5
23
A 2 Q 4 2 N 2 2 1 9 11.0
11.8
check the alignment of the signal generator.
1,2
3
3.5
A6Q1
2N706
2.3
1,2
6.2
2.13
A6Q2 2N706 2.3
1,2
1.3
0.62
A6Q3 2N930 0
trace circuits and to isolate the faulty part.
1,2
25
1.3
A6Q4 2N930 0.66
Junction 1N1614 44
CR6-CR7
2-7. In-Circiut Transistor Tests
Junction 1N1614 18
CR10-CR11
a. General. Chart b b e l o w p r o v i d e s v o l t a g e
Notes. 1. RF OUTPUT to 62.5 KUV
measurements taken with the transistors con-
2. FUNCTION to FREQ CAL
nected in the circuit. All measurements are made
3. FUNCTION to 400 HZ
4. DEVIATION RANGE -KHZ to 10
with the vtvm connected between the listed point
5. DEVIATION fully counterclockwise
and chassis ground.
6. AUDIO VOL fully counterclockwise
2-5
