TM 11-6625-1831-13
5-3b.
Troubleshooting Test Panel (Cont)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
41. AUDIO OUT signal frequency is not 8 to 15 Hz
Step 1.
Check OSC switch S14 and MULT switch S11. Remove Oscillator and Switch Module 1A2
Test for open circuit through S14 from XA2-E to XA2-7. Test for open circuit through S11 from
XA2-5 to 1TB1-3, and also from XA2-6 to 1TB1-2. Each reading should be zero ohms.
Repair wiring or replace switch as necessary (para 5-14, 5-6).
Step 2.
Check TARGET LEVEL potentiometer R6 and FREQ potentiometers R3A and R3B Remove
Oscillator and Switch Module 1A2. Test resistance through R6, R3A, and R3B from XA2
connector See schematic for pin numbers and resistance values.
Repair wiring or replace potentiometer as necessary (para 5-14, 5-6).
Step 3.
Check capacitors C2 and C3, and resistor R4 (located on 1TB1). See schematic for pin
numbers and values.
Replace defective components (para 5-5).
Step 4.
Check Oscillator and Switch Module 1A2 by replacing it.
Install new module (para 5-6).
42. AUDIO OUT signal frequency is not 100 to 140 Hz.
Step 1
Check FREQ potentiometers R3A and R3B. Remove Oscillator and Switch Module 1 A2. Test
resistance through R3A from XA2-5 to TB1-5. Test resistance through R3B from XA2-5 to
TB1-7. Each reading should change from 0 to 2500 ohms as the knob is turned
Replace defective potentiometer (para 5-6).
Step 2.
Check Oscillator and Switch Module 1A2 by replacing it
Install new module (para 5-6).
43 AUDIO OUT signal frequency is not 700 to 1300 Hz.
Step 1.
Check MULT switch S11. Remove Oscillator and Switch Module 1 A2. Test continuity through
S11 from XA2-5 to TB1-4, and from XA2-6 to TB1-1. Each reading should be zero ohms
Repair wiring or replace switch as necessary (para 5-14, 5-6).
Step 2.
Check capacitors C1 and C4 (on 1TB1) See schematic for pin numbers and values
Replace defective components (para 5-5).
Step 3.
Check Oscillator and Switch Module 1A2 by replacing it
Install new module (para 5-6).
44. AUDIO OUT signal too high.
Check Oscillator and Switch Module 1A2 by replacing it.
Install new module (para 5-6).
5-36
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