Axcera-430B FCC Type Acceptance Report Parts List/Tune-up Info
February 2004
7-9
2. Connect a sync and black test signal to the video input jack of the remote interface
panel.
3. Adjust manual gain pot R5 on the AGC control board for:
•
Sync + black 0 IRE setup; wattmeter=360 watts
•
Sync + black 7.5 IRE setup; wattmeter=325 watts
Note: The transmitter must have 40 IRE units of sync.
4. Obtain a zero span reference of the visual-only carrier on a spectrum analyzer.
Replace the J16 connector on the sync tip clamp/modulator board in the exciter tray.
Adjust R5 on the AGC control board until the same visual reference is obtained. Adjust
R44 on the AGC control board for 100% Forward Power.
Lower the forward power reading to 80% on the front panel meter using R5, the manual
gain adjust on the AGC control board. Tune R65, the AGC fault adjust on the AGC control
board, until the green Module LED DS3 on the front panel just begins to light. Use R5 to
re-adjust the forward power to 100%.
Switch off the tray and reverse the J6 and J7 cables on the 3-way combiner board.
Switch on the tray and adjust the front panel meter, in the Reflected Output Power
position, to a 100% reading using R53, the reflected power meter adjust on the AGC
control board. Adjust the reflected output power to a 20% reading using R5 on the AGC
control board. Tune R59, the VSWR cutback adjust on the AGC control board, until the
red VSWR Cutback LED DS4 on the front panel lights. This sets up the VSWR cutback
circuitry.
Readjust R5 for 100% on the meter to achieve a 600 watts peak of sync + aural output.
However, if the system requires less output power per amplifier tray, adjust each tray by
the same amount to give the desired total output power.
Switch off the tray and return the J6 and J7 cables on the 3-way combiner board back to
their original positions. If the tray was originally operating below 100% output power, the
AGC fault adjust was set for 20% below the operational % Output Power of the tray. See
the Test Data Sheet for the transmitter for the actual readings for the tray.
Place S1 on the AGC control board in the AGC position. This is the normal operating
position after the setup is completed.
There are spare 1-amp and 10-amp fuses on the top, right-hand side of the tray. These
are replacements for fuses on the current metering board.
At this point, the 600-watt amplifier tray is aligned, calibrated, and ready for normal
operation.
