TM 11-6625-584-45
Probable
Trouble
Correction
Symptom
check for 12 volts dc between TP5
5. Cont.
(+) and TP6 (-). If no voltage is
present, check transistors Q8 and
Q16 and associated components.
Repair or replace defective part.
Refer to figure 6-8(1).
Perform voltage and resistance
Board A1A1 defective.
6. No signals available at both
measurements to find defective
HI-RF and LORF output
part. (para 2-7). Refer to figures
jacks.
Check and replace defective part. Refer
7. No output at LO-RF jack, output
Coil A1A2L1, A1A2L2 or board
A1A2A1 defective.
at HI-RF jack normal.
Check for RF signal at A1J1. If
Transistor A1A1Q2 or A1A1Q3
8. No output at HI-RF jack, output
absent, check and replace defective
defective.
at LO-RF jack normal.
part. Refer to figures 2-11 and
6-8(3).
Check operation of switch with multim-
RF OUTPUT switch A4S1 defective.
eter. Repair or replace defective
part. Refer to figures 2-18, 2-19,
and 6-8(3).
Check for negative dc voltage at junc-
Diode A1A2A1CR1 defective.
9. Normal output at LO-RF jack,
tion of A1A2A1CR1 and A1A2A1C1
no indication on IF UV RF
SET TO LINE meter.
tive part. Refer to figure 6-8 (3).
Check and replace defective part. Refer
Resistor R61 or switch A4S1 defective.
to figures 2-4 and 6-8 (3).
Check for negative dc voltage at
Diode A4CR1 defective.
10. Normal output at HI-RF jack,
junction of A4CR1 and A4C1. If
no indication on IF UV RF
absent replace defective part. Refer
SET TO LINE meter.
to figures 2-18 and 6-8 (3).
Check and replace defective part.
Resistor A4R1 or switch A4S1
Refer to figures 2-18 and 6-8(3).
defective.
Check for output at INT MOD OUT
DEVIATION meter Ml or meter
11. With FUNCTION switch turned
jack J4. If present, repair or replace
amplifier-detective Q5 defective.
to 150 HZ, 400 HZ, 1000HZ
defective part. Refer to figures 2-7
position, no output appears on
and 6-8(2).
DEVIATION meter.
Connect external modulation signal
Modulation amplifier Q3, Q4 or AF
to EXT MOD jack. Turn FUNC-
oscillator Q1, Q14, Q15 defective.
TION switch to EXT MOD. If indi-
cation appears on DEVIATION
meter, repair or replace AF oscilla-
tor Q1, Q14, Q15. If no indication
appears on DEVIATION meter, re-
place modulation amplifier Q3, Q4.
Repair or replace defective part.
Isolation amplifier Q6, Q17 defective.
12. DEVIATION meter indication
Refer to figures 2-6 and 6-8 (2).
normal, output RF signal not
being modulated.
Check for IF signal at P3. If present,
IF attenuator assembly A3.
13. With FUNCTION switch turned
IF attenuator assembly defective;
to IF, no output appears at
check and replace defective part.
IF output jack for any position
Refer to figures 2-16, 2-17, and 6-8
of IF MHZ switch.
(4).
Check for IF signal across A2A1T3.
Amplifier A2A1Q3 A2A1Q4 defective.
If present, repair or replace ampli-
fier A2A1Q3, A2A1Q4.
Refer to figure 2-15 and 6-8(4).
Check for IF signal across A2A1T2.
Crystal-controlled oscillator A2A1Q1
If absent, repair or replace A2A1Q1,
A2A1 Q2 defective.
A2A1Q2.
Check for 1.000 MHZ signal at A6TP1.
14. Loss of audio beat notes at 1
Oven A6A1A1 defective.
If absent, replace A6A1A1. Refer to
MHZ intervals.
2-4
