Control/Interface Board Interface (PC4J10)
Jack – Pin #
Function
2
6
22
J1 – 17
PWR REF OUT: This voltage, proportional to the monitored output power,
originates from the front panel AGC ADJUST R15 and reaches PC1J6-8 of the
IF/Converter through PC4J10-17 and PC4J8-8. This signal acts as the power
reference for the IF/Converter’s output AGC loop by controlling variable
attenuator PC1CR9/CR10 and compensating for any power variations occurring
at the Exciter’s/transmitter’s output. If for some reason the Exciter’s/transmitter’s
output power were to drop, the positive voltage at PC4J8-8 would drop reducing
the attenuation provided by PIN diodes PC1CR9/CR10 in proportion to the power
decrease, thereby bringing the output power back to its appropriate operating
level. In the case where the Exciter’s/transmitter’s output increases above its
rated output, the PWR REFERENCE voltage at PC4J8-8 will increase causing
attenuator PC1CR9/CR10 to increase signal resistance, decreasing the output
level to its proper value.
J1 – 18
AGC/MANUAL LED: AGC ACTIVE LED DS6 will light when a high is present at
this input forward biasing transistor Q6 which is connected to PC4U4C-8 via R23.
Indicator DS6 will be lit only when concurrent highs are provided from the
OPERATE/SWEEP switch PC4S1 (OPERATE position), from the AMP STATUS
IN line at PC4J4-1, from the front panel AGC/MANUAL switch S2 (AGC position)
at PC4J10-9 and from the REMOTE AGC ON/OFF line at PC4J5-6, forcing the
output of PC4U4C high.
J1 – 19
PWR REF IN: This voltage, proportional to the monitored output power,
originates from either the Exciter (A3J3-5) or transmitter (A7A1J3-5) Metering
Detector and is buffered by PC4U5A or PC4U7A, respectively. The voltage is
forwarded to the front panel AGC ADJUST R15 through PC4JP1 and PC4J10-19
to variable gain amplifier U1. The amplitude of the voltage is controlled by R15
and reaches the IF/Converter through PCJ10-17 and PCJ8-8. The voltage acts
as the reference for the IF/Converter’s output AGC loop by controlling variable
attenuator PC1CR9/CR10 and automatically compensating for any power
variations occurring at the Exciter’s/transmitter’s output. If for some reason the
Exciter’s/transmitter’s output power were to drop, the positive voltage at PC4J8-8
would be reduced cutting the attenuation provided by PIN diodes PC1CR9/CR10
in proportion to the power decrease seen at the Exciter’s/transmitter’s output,
thereby bringing the power back to its appropriate operating level. In the case
where the transmitter’s output increases above its rated power, the PWR
REFERENCE voltage at PC4J8-8 will increase causing attenuator PC1CR9/
CR10 to add signal resistance, decreasing the Exciter’s/transmitter’s output level
to its proper value.
J1 – 20
SWEEP MODE LED: This input controls the operation of the front panel
SWEEP MODE LED DS4. With the OPERATE/SWEEP switch PC4S1 in the
SWEEP (low) position, PC4U3C supplies a low to PC4J10-20 and control
transistor Q4 which is forward biased to turn DS4. Placing switch PC4S1 in the
OPERATE position will generate a high causing the SWEEP MODE indicator to
go out.
