Control/Interface Board Interface (PC4J10)
Jack – Pin #
Function
2
6
23
J1 – 21
LEVEL ADJUST IN: Assuming the outputs of AND gates PC4U1A/U1B/U1D/
U2C/U2B/U2D/U2A are high, amplifier PC4U8A provides a reference of approxi-
mately 14V at this input which is fed to front panel LEVEL ADJUST potentiome-
ter R16. This potentiometer enables manual adjustment of IF/Converter variable
attenuator PC1CR7/CR8 and, therefore, manual control of the Exciter’s/
transmitter’s output power. If one of the above mentioned AND gates shifts low
due to a fault signal or command from:
J8-6
IF STATUS
S1
OPERATE/SWEEP
J6-3
2W AMPL STATUS
J2-8
LOCK STATUS
J9-1
REFL PWR
J5-1
REMOTE OP/STBY
J4-5
VIDEO SENSE
J10-7
OPERATE/STANDBY
then a negative voltage will emanate from PC4U8A and pass through
PC4J10-21, LEVEL ADJUST R16, J1-23, PC4J10-23, PC4J8-7, PC1J6-7 and
PC1U9-5, increasing the IF attenuation of PIN diodes PC1CR7/CR8 and
significantly reducing the output power of the Exciter/transmitter, placing the unit
in standby.
J1 – 22
SYNTH LOCK LED: This input controls the activation and deactivation of the
front panel SYNTHESIZER LOCK light DS2. The voltage originates at
A2A1J3-A as an operational indicator for the Synthesizer. A low (synthesizer
locked) from PC4J2-8 to the base of PC4Q1 will place a high at the inputs of
AND gate PC4U1A-1 & 2 forcing its output high. This high is passed through
PC4R5 and PC4J10-22 forward biasing Q2 causing DS2 to light. If Synthesizer
A2A1 unlocks, a high will be sent to PC4J2-8 which ultimately shuts off the
SYNTHESIZER LOCK indicator DS2.
J1 – 23
LEVEL ADJUST OUT: This voltage is developed in amplifier PC4U8A and sent
through LEVEL ADJUST R16 and passed from this output (J1-23) to PC4J8-7
as a control level for variable attenuator PC1CR7/CR8 in the IF/Converter (see
J1-21 above).
J1 – 24
IF STATUS LED: This signal is taken from the output of PC4U4B via resistor
PC4R19 to control IF STATUS LED DS5. With the presence of an IF signal at
the input of PC1, a high is provided from PC1U4A to PC4U4B, lighting IF
STATUS indicator DS5 via PC4R19, PC4J10-24 and control transistor Q5. If the
IF input is removed from PC1J1, PC1U4 will then provide a low to PC4U4B
extinguishing the IF STATUS LED DS5 while forcing U3D and U2A low.
J1 – 25
OUTPUT AGC VOLTAGE: This voltage drives the front panel AGC meter
DS12. From PC1J6-9, a ±15V signal is transformed to a 0 to +15V level by
PC4U8B and sent to PC4J10-25 and is used to drive the front panel AGC meter
employing LED Bar Graph Driver U3.
