Southern Avionics Company SD100 Manual Do Utilizador
SD SERIES TRANSMITTER
106
•
•
•
•
•
•
SOUTHERN AVIONICS COMPANY
4.3 TRANSMITTER
4.3.1 PA POWER SUPPLY ALIGNMENT (PAPS)
Safety Note: Dangerous voltages are present on this PCB during power on tests. Be very careful when working on
this board. When power is removed dangerous voltage will still be present on the HV cap bank. A built in HV
Bleeder on the mother board will discharge the HV cap bank in about 30 seconds. Red LED DS1 will be on if power
is present. Another LED on the mother board will also indicate HV presence. Verify this with a meter check at either
end of R69 until you are personally confident the bleeder circuit and associated indicators are operating correctly.
this board. When power is removed dangerous voltage will still be present on the HV cap bank. A built in HV
Bleeder on the mother board will discharge the HV cap bank in about 30 seconds. Red LED DS1 will be on if power
is present. Another LED on the mother board will also indicate HV presence. Verify this with a meter check at either
end of R69 until you are personally confident the bleeder circuit and associated indicators are operating correctly.
Note: To be able to successfully complete this alignment without using special loading fixtures we rely on a normal
load being presented to the supply by the RF Power Amplifier PCB and Filter PCB. Therefore it is important that
those PCBs be aligned and in good working order.
load being presented to the supply by the RF Power Amplifier PCB and Filter PCB. Therefore it is important that
those PCBs be aligned and in good working order.
1.0
PRELIMINARY CHECKS AND ADJUSTMENTS
1.1
Verify that all ac and dc power switches are turned off .
1.2
Connect a PC to the Controller / Monitor local port with an RS232 null modem cable.
1.3
Turn the PC on and Load and Run the Controller / Monitor user Software supplied with the System
1.4
Remove the RF power amplifier PCB which removes the load from the PAPS
1.5
Remove the PAPS PCB and place it on the extender fixture.
1.6
Adjust R32,R38,R15, R41, R43, R48 and R66 fully clockwise (CW)
1.7
Adjust R4, R7, and R40 fully counterclockwise (CCW)
1.8
Adjust R45 and R46 for middle range
1.9
Toggle the Manual HV switch S3 to the OFF position (actuator thrown toward the front of the PCB)
1.10 Move jumper JP1 to 3-4 (lower position) enabling local power control
2.0
DC CONTROLLER SECTION LOW VOLTAGE ALIGNMENT
2.1
Turn the main power AC switch on. . Caution! Input HV is on!
2.2
Turn the AC distribution switch for Transmitter 1 or Transmitter 2 on depending on where the extender is
being used.
being used.
2.3
Verify the presence of +50vdc on TP1 of the RF motherboard in use.
2.4
Adjust R43 for 12.00
±0.1 vdc at TP11
2.5
Adjust R48 for 12.00
±0.1vdc at TP13
2.6
Press the manual reset buttons S1 and S2
2.7
Adjust r4 for 4.00
±0.01vdc at TP1
2.8
Initially adjust R7 for approximately 2.7vdc at TP5
2.9
Scope TP2 and further adjust R7 until an approximate 50% duty cycle 75khz square-wave is seen. A loose
feel to the adjustment is normal since HV feedback which stabilizes the signal is not yet present.
feel to the adjustment is normal since HV feedback which stabilizes the signal is not yet present.
2.10 Read TP2 with a calibrated frequency counter and adjust R20 for 75 kHz
±500 Hz. Note that this
frequency is not critical but is optimum for the inductor used in the buck converter.