Datron TW7000MS, Technical Manual

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4: Technical Description Synthesizer Board
4-24 TW7000MS
4.3.2
Test Procedures
These test procedures require the following equipment:
• Oscilloscope
• SINAD meter
• Frequency counter
• Multimeter
• Power supply 0-20 Vdc
• Wattmeter
• -30 dBm Attenuator dummy load
• Two-tone test box
• Signal generator
• Extender card set
Alignment 1. Set the power supply for 13.8 Vdc.
2. Place the scope probe (x10) on J54. Adjust L7 for a maximum signal
(approximately 480 mVAC, 70 MHz).
3. Place the scope probe on the bottom of R15 above J55 and adjust L1 for
exactly 3 Vdc (ensure scope is set for DC).
4. Place the scope probe on U3, pin 3 (set the scope to a 10 mv scale, 20 ms
time). Adjust L13-L17 for a maximum signal (approximately130 mVPP
minimum).
5. Set the radio frequency to 30.00 MHz. Carefully adjust L5 for 10 Vdc
±.25 at U5, pin 1.
Miscellaneous
Test 1. Measure the voltage at U5, pin 8 for 9 Vdc ±.5V.
2. Verify that the RX tone is present with the signal generator set at
-113 dBm and 8.001 MHz, and the radio at 8 MHz USB. SINAD should
be approximately 10 dB or better. At -75 dBm level, the audio should be
approximately 3V or better with maximum volume and the radio’s
speaker off.
3. At -113 dBm input, check SINAD at various frequencies from 1.6 to 30
MHz (this verifies that the synthesizer is locking).
4. With the signal generator set to 8.001 MHz +6 dBm level, turn carrier off,
then on. The RX tone should sound normal.