Fluke 6080A - FM ADJUSTMENTS 6 E-16.; Adjustments on the Modulation Control PCA (A11) 6 E-17.

TROUBLESHOOTING AND REPAIR
FREQUENCY AND PHASE MODULATION
FM ADJUSTMENTS 6E-16.
This alignment includes the following PCAs:
• A11, 6080A/AN-4048 MOD CONTROL, The FM modulation section
• A14, 6080A/AN-4045 FM Oscillator
The following equipment is recommended to make FM adjustments:
DMM (Fluke 8840A)
Modulation meter (HP 8901A)
LFSSG (Fluke 6011A)
Spectrum analyzer (HP 8586)
Oscilloscope (Tektronix)
Adjustments on the Modulation Control PCA (A11) 6E-17.
NOTE
This procedure concerns the adjustment of the modulation circuitry.
Other adjustments are covered in other procedures.
Make adjustments on the Modulation Control PCA as described in the following
procedure:
1. Make the following equipment settings:
a. Set the UUT to SPCL 909, 800 MHz, 0 dBm, 4 MHz dev, EXT ACFM.
b. Set the 8840A DMM to AC volts, autorange.
c. Set the 6011A Signal Generator to 1 kHz, 383 mV RMS.
2. Connect the 6011A to the UUT EXT FM input and to the 8840A.
3. Set the 6011A (as measured by the 8840A) to 707 mV RMS. Set the 8840A to AC
volts, and autorange. Connect the 8840A to J16-P1 on 4048 Modulation Control
PCA. Adjust R82 for 2.828V RMS ± 2 mV.
4. Set the UUT to 700 MHz. Set the 8840A to AC volts, autorange. Connect the
8840A to J16-P1 on 4048 Modulation Control PCA. Adjust R102 for a reading of
2.828V RMS ± 2 mV on the 8840A.
5. Set the UUT EXT ACFM off and set the UUT INT FM on. The 8840A should read
2.828V RMS ± 2 mV RMS.
Set UUT INT FM off and set UUT EXT ACFM on.
6. Set the UUT to SPCL 943. Connect the 8840A to J2-P14. Set the 8840A to DC
volts. Adjust R99 for 10.24V DC ± 10 mV.
Connect the 8840A to J1-P3. Set the 8840A to DC volts. Adjust R101 for 10.24V
DC ± 10 mV.
Connect 8840A to J6-P24. Verify that the 8840A reads 10V DC ± .1V DC.
6E-13