Figure 10-4. Antenna Tuner A2A2 Performance Test (Sheet 1 of 3)

TM 11-5820-919-40-2

ANTENNA TUNER PERFORMANCE TEST

NOTE 1:

Changing the MODE switch from V-TR to V-RCV to V-TR causes a tune start signal

to be routed from the modulator/demodulator. This will cause all capacitive and

inductive elements to be removed from the rf pathway. When PIT or CW key is

closed. the inductors and capacitors are added.

NOTE 2:

A voltage difference of 1.5 vac or greater across the coil indicates that the relay is

open. The coil is then in the rf pathway. After a time start, and before PTT is

closed, all coil relays should be closed.

NOTE 3:

If a coil is replaced, be sure that its inductance is exactly (11 percent) one-half of

next larger coil.

NOTE 4:

Unless otherwise specified, all voltage measurements taken with respect to ground.

NOTE 5:

Hybrid binary count faults can be investigated in the following way:

1. Monitor TP10 with DVM and record voltage measurement.

2. Set TP10 to 0v (this disables comparator) by adjusting R4.

3. Monitor bases of S and R driver transistors for RL1 thru E111 and came pare

waveforms to those of a functional module (see that the " "count is performed

properly).

4. Set TP10 to +6v by adjusting R4.

5. Monitor TP8 and TP9 with DVM and record voltage measurement.

6. Set TP8 and TP9 to +0v (this disables comparator) by adjusting R2 and R3,

respectively.

7. Monitor bases of S and R driver transistors for KC1 thru KC8 and compare

waveforms to those of a functional module (see that the " "count is performed

properly).

8. Reset TP8, TP9, TP10 to the values recorded in steps 1 and 5.

NOTE 6:

Component failures due to untraceable faults require special handling at a factory or

depot location using a test fixture and a vector impedance meter. If performance is

not satisfactory, and a tune-fault coca not occur, then refer module to fifth echelon

repair level.

Figure 10-4. Antenna Tuner A2A2 Performance Test (Sheet 1 of 3)