Figure 5-4. Synthesizer A1A3 Performance Test (Sheet 1 of 2)

TM 11-5820-919-40-2

SYNTHESIZER PERFORMANCE TEST

NOTE 1: Spurious signal applies between 4.995 and 5.005 MHz. Set spectrum analyzer at:

Log Reference Level

10 db

Linear Sensitivity

Bandwidth

1 kHz

Scan Width

10 kHz/div

Scan Time

2 sec/div.

Video Falter

10 Hz

Center Frequency

5 MHz

10 db Log

Input Attenuation

30 db

Range

0-110 MHz

Storage

STD

Scan Mode

SINGLE

NOTE 2:

Spurious signal applies between 40 and 90 MHz. Set spectrum analyzer at:

Log Reference Level

Linear Sensitivity

Bandwidth

300 kHz

Scan Width

10 MHz/div.

Scan Tome

10 ms/div.

Video Falter

10 kHz

10 db Log

Input Attenuation

20 db

Center Frequency

70 MHz, USB

Range

0-110 MHz

Scan Mode

INT

NOTE 3:

A3J1 output IS frequency kHz plus 75,000 kHz. Spurious applies between 60 and 110 MHz.

If output power IS low, adjust R19 of VCO (U3). If unable to raise power, continue with

troubleshooting flowchart.

NOTE 4:

Spurious signal applies between 60 and 110 MHz. TP5 frequency is 70,090,000 Hz + XY,

where X is 1 kHz frequency kHz digit and Y is 100 Hz frequency Hz digit. Set spectrum

analyzer as in Note 2, except that the center frequency is 91 MHz.

NOTE 5:

When 1 kHz digit of frequency kHz is 0, TP15 voltage is 3v. When this same digit is 9, TP15

is 9v.

NOTE 6:

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

NOTE 7:

If the phase locking action of the synthesizer is functioning correctly, TP4 voltage would be

6v. Since it IS not locking, U2 should be pruned at one end or the other of the 3 to 9v VCO

tune voltage.

NOTE 8:

Low frequency adjust transformer T3 must be replaced and returned as specified on

paragraph 5-9 whenever low frequency loop filter hybrid (U5) is replaced.

TM-07748A-45/3

Figure 5-4. Synthesizer A1A3 Performance Test (Sheet 1 of 2)