Control/Interface Board Interface (PC4J10)
Jack – Pin #
Function
2
6
21
R16 causes IF input attenuator PC1CR7/CR8 to provide maximum attenuation.
The Exciter and transmitter are now in standby with OPERATE LED DS7
extinguished.
J1 – 9
AGC/MANUAL: An open or ground will appear here depending on the position
of the front panel AGC/MANUAL switch S2 which determines the IF/Converter
(PC1) output AGC is active (switch in) or fixed (switch out). Releasing the front
panel AGC/MANUAL switch will supply a ground to PC4U4A-2 causing the
outputs of PC4U4D/U4C to go low. This low forces IF PIN diodes PC1CR9/
CR10 to stabilize at the center of their attenuation range (
3dB) thereby
inhibiting the output AGC while extinguishing front panel AGC ACTIVE LED DS6
via PC4J10-18, J1-18 and Q6. With the AGC/MANUAL switch pressed in, a high
will appear at PC4J10-9 and, assuming all other inputs to U4C, U4D and U4A
are high, the high at PC4J8-10 will release switch PC1S2, remove the ground
from PC1U18 and release diodes PC1CR9/CR10 to respond to the normal output
AGC voltages while AGC ACTIVE lamp DS6 turns on.
J1 – 11
VSWR LED: Illumination and deactivation of VSWR OVERLOAD LED DS9 is
controlled by the voltage at the base of transistor Q8 delivered from flip-flop
PC4U9A-6 via PC4J10-11. Under normal operation PC4U9A-6 is low keeping
Q8 back biased and DS8 off. With a VSWR overload, PC4U9A-6 changes state
for causing Q8 to conduct and DS8 to light.
J1 – 13
VSWR RESET: S3 is a momentary switch which sends a ground to reset pin 4
of VSWR overload flip-flop PC4U9A changing the states of pins 5 & 6 to their
normal Q/high and Q NOT/low outputs. As a consequence, the high activating
VSWR OVERLOAD light DS8 is removed turning off the front panel indicator.
A high now appears at PC4U2D-13 sending PC4U2A-3 and PC4U8A-1 in the
same direction after ramp-up circuit PC4R26/R27/CR1/CR17 charges. The
positive voltage at PC4J10-21 proceeds to LEVEL ADJUST R16 finally causing
buffer PC1U9 to release IF input attenuator PC1CR7/CR8 to normal attenuation.
This action brings the Exciter and transmitter out of standby by slowly increasing
the unit’s output power to normal.
J1 – 14
REFL PWR: No connection
J1 – 15
FWD PWR: A voltage proportional to the forward output power of the Exciter is
provided from Metering Detector A3J3-5 via PC4J9-5, PC4U5A and amplifier
PC4U7B whose gain is controlled by FWD PWR METER ADJ PC4R42. This
potentiometer is adjusted for PC4U7B to provide enough voltage for a 100%
reading on the front panel RF POWER meter DS9/10/11 when the Exciter is
providing its proper output power. This voltage is supplied to the meter through
PC4J10-15, squaring circuit U2, amplifier PC3U1 and LED Bar Graph Drivers
U4/U5/U6.
J1 – 16
LIN CORR ACTIVE: With Linearity corrector switch PC2S1 in the ENABLE
po5V is presented to input pins 9 & 10 of PC4U1C via PC4J7-3. The
resulting high at PC4U1C-8 is forwarded to PC4J10-16, J1-16 and Q3 used to
turn on front panel LINEARITY CORRECTOR light DS3.