Operation Manual

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measured with the 3710.
DDM Check that the CL DDM readings are the same as with 3710.
ADJUSTMENT (NF CHANNEL):
Pre-check Check that all monitor inputs from MCU are correct. (Use field measurement
instrument NM3710). Make a note of the values.
RF-level Set R3338 in middle position. Set strap fields S++ on connector P3002 and
adjust R3338 until TP3023 reads 240mV. Adjust RF potentiometer R3342 on
front of MF1219 card until NF RF level reads exactly 3,0 volts.
AGC Time Adjust AGC timing pot R3049 until the DC value measured at TP4 are the
same with transmitters on and off.
SDM Adjust SDM pot R3048 until the NF SDM readings is the same as the value
measured with the 3710.
DDM Check that the NF DDM reading is the same as with 3710.
CHECK:
Power down system. Remove the extension card and place the MF1219 inside cabinet. Turn
transmitters on.
Monitor Use RMM software to check monitor readings for all four channels. RF level
should now be 3.0V, SDM 40% and DDM 0,0%. It might be necessary to make
small adjustments to the RF Level with potentiometers R342 (DS), R1342
(CLR), R2342 (CL) and R3342 (NF).
Maintenance Use RMM software to check maintenance values for MF1219 card. There shall
be no warnings (if the transmitters are on).
7.3.3 PS1227 replacement
PREPARATIONS:
Power down system. Remove old unit and place the new unit in the vacant slot.
ADJUSTMENT:
No adjustments are necessary.
CHECK:
System: Remove the other PS1227 unit. Turn transmitters on and set the correct trans-
mitter to air (Transmitter 1 to check Powersupply 1). Check the monitor read-
ings to verify correct transmitter behaviour.
Maintenance Power down the ILS, re-insert the other PS1227 unit, and power up again.
Check the RMM maintenance readings of the PS1227 system voltages; check
both powersupplies.
7.3.4 OS1221 replacement
PREPARATIONS:
Power down system. Remove old unit. Write down the strap settings of the old OS1221A
(LLZ) or 1221B (GP) card and make sure the new card is identically configured. Please refer
to Appendix B to verify the frequency selection.
ADJUSTMENT:
The frequency of the RF output signal is normally factory adjusted. To adjust the frequency,
power down the ILS, remove the shield, place the OS1221 card on an extender board and
adjust by fine-tuning the capacitor C1. Turn off 90, 150 and 1020 Hz modulation tones from