TROUBLESHOOTING AND REPAIR
FREQUENCY SYNTHESIS
80-MHz Level Adjustment, R617 6C-23.
TEST EQUIPMENT:
• Spectrum analyzer
REMARKS:
The 80-MHz Level Adjustment is normally required only when Q606, Q609, Q610,
U601 and associated components have been replaced, or when the adjustment has been
changed or has shifted. This adjustment should be done after L612 and L613 have been
adjusted.
PROCEDURE:
The 80-MHz Level from A2-J5 is adjusted to 4 dBm.
1. Program UUT to SPCL 909.
2. Remove the cable from A2-J15. Connect A2-J15 to the spectrum analyzer. Set the
spectrum analyzer to 80 MHz, 1 MHz-span and 10-dBm reference level.
3. Adjust R617 for 4 dBm ±0.2.
4. Reconnect the cable to A2-J15.
2-MHz Notch Adjustment, L205 6C-24.
TEST EQUIPMENT:
• Spectrum analyzer
REMARKS:
The 2-MHz Notch Adjustment is normally required only if L205 and associated
components have been replaced or when the adjustment has shifted.
PROCEDURE:
The 2-MHz signal, at the output of the acquisition oscillator, is minimized.
1. Program the UUT to SPCL 909.
2. Program the UUT to 15.25 MHz.
3. Connect the spectrum analyzer to TP6 with clip leads. Set the spectrum analyzer to
center 2 MHz, 100-kHz span, and ref level -20 dB.
4. As L205 is adjusted inward, a signal should be visible on the spectrum analyzer.
Adjust L205 to minimize this signal.
6C-30
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