AR 25A250B - Control System and Regulator Board; Control System; Voltage Regulator Board

Model 25A250B
18 Rev A
Power Supply PS2 is a single output supply which provides +28VDC to the RF final stage and to the
A10 Voltage Regulator board. Primary AC circuit protection is provided by the circuit breaker in the
Power Entry Module.
3.4 CONTROL SYSTEM
3.4.1 A4 Control/Fault Board (Schematic #10042218)
The A4 Control/Fault board consists of one 16-bit microcontrollers and several other ICs that monitor and
indicate the status of the amplifier. Power is supplied using only a single 5-volt power supply. The board
offers the following:
Feature
Quantity
Open drain outputs
4
Digital outputs
6
Digital inputs (5-volt tolerant)
24
Analog outputs
2
2-channel encoder input
1
Inputs for a keypad
6
Display connectors
1
Serial communication jacks
2
3.4.2 A5 Interface Board (Schematic #10020073)
3.5 A10 VOLTAGE REGULATOR BOARD
The A10 Voltage Regulator Board contains two adjustable positive voltage circuits employing Linear
Regulator ICs U4 and U5. U4 accepts a +28 VDC input and outputs the +26.5 VDC Drain Voltage for the A1
preamp stage. U5 accepts a +28 VDC input and outputs the +20.5 VDC supply voltage for the B1 Fan
Assembly.