Display/Monitor Interface (PC3J1)
Jack – Pin #
Function
2
6
20
J10 – 25
OUTPUT AGC VOLT: This voltage is used to drive the front panel AGC meter
PC3DS12. From PC1J6-9 a ±15V signal is transformed to a 0 to +15V level by
U8B and sent to J5-4 and J10-25. The voltage at J10-25 is used to drive the
front panel AGC meter via PC3J1-25 and LED bar graph driver PC3U3.
J10 – 26
AMPLIFIER STATUS LED: This high or low voltage originates from A1J3-3 to
indicate the status of the transistors within the 2W UHF Amplifier module. A high
at J6-3 and U3A-3 indicates that the devices are operating properly while lighting
AMPLIFIER STATUS LED PC3DS1 via R8, J10-26, PC3J1-26 and PC3Q1. A
low at the output of U3A indicating a device failure within the amplifier will
extinguish the front panel AMPLIFIER STATUS LED PC3DS1 via the same path.
2.2j
Display/Monitor Board:
Schematic Diagram 30404041/Rev 52
t
A2PC3
Current Draw
33mA @ +15V
7mA @
15V
300mA typ./360mA max. @ +5V
The Display/Monitor board is positioned behind the front panel of the drawer and contains the
indicator lights, adjustments and switches necessary to operate and maintain the EMEX1 Exciter.
Control/Interface Board Interface (PC4J10)
Jack – Pin #
Function
J1 – 1
+5V: From PC4J10-1
J1 – 2
GND: From PC4J10-2
J1 – 3
15V: From PC4J10-3
J1 – 5
+15V: From PC4J10-5
J1 – 7
OPERATE/STANDBY: An open or ground is provided at this pin to PC4J10-7
from OPERATE/STANDBY switch S1 placing the Exciter/transmitter in an active
(switch in ) or inactive (switch out) mode. With S1 in, transistor Q7 will conduct
causing OPERATE LED DS7 to illuminate while sending a high to AND gate
PC4U1D. If its associated gates PC4U1B through PC4U2A are also high, 500W
Power Amplifier A3 will activate via PC4J4-3 (AMP BIAS CONTROL) due to the
high from PC4U2C-8. Simultaneously, the voltage at PC3J10-21 will remain
normal through LEVEL ADJUST R16, holding IF input attenuator PC1CR7/CR8
at its previously set value for proper Exciter/transmitter output power. With S1
released, a ground at PC4U1D-12 will force logic lows at the outputs of the
succeeding AND gates resulting with a low at PC3J4-3 making the 500W UHF
Power Amplifier inactive. The negative at PC3J10-21 through LEVEL ADJUST
