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panel board from the A2 Control Board. The V-MON and I-MON signals are then. amplified by buffer amplifiers before
they are directed to their respective digital voltmeters for display. As an intermediate step before display, the V-MON
signal passes through a pair of bilateral range switches A3U4A and U4D which determine the resolution of the voltage
display. When the voltage to be displayed is below a certain value, the unit selects the low-range bilateral switch A3U4
which enables the voltage to be displayed to an accuracy of two decimal places; however above this critical output voltage
value, the high-range switch A3U4D assumes control and the voltage displayed is accurate to one decimal place.
In addition to providing the display voltage, the V-MON and I-MON signals are used to generate the CV and CC control
voltages respectively. When the CV control voltage is found to be more negative than the Control Port Voltage, the power
supply is operating in the CV Mode and the CV LED lights. Similarly the CC LED lights when the CC Control Voltage is
below the Control Port Voltage confirming that the power supply is operating in CC Mode. When both CV and CC Control
Voltages exceed the Control Port Voltage, the power supply becomes unregulated and the unregulated LED lights.
The CV of CC Program voltages are obtained by depressing the "DISPLAY SETTINGS" switch and reading the respective
display. By depressing this switch and turning the Voltage or Current control, the technician can set the program voltage or
current. If the instrument is operating in CV Mode for example, then the display voltage and the CV Program Voltage are
identical but the display current may vary with the CC Program Voltage. This condition is reversed when the unit is under
CC Mode.
The OVP set potentiometer is also located on the front panel. By depressing the “OVP DISPLAY” switch and adjusting the
pot with a small flat screw-driver, the OVP limit can be set. When the output voltage exceeds this pre-set limit, the unit is
disabled and the OVP LED lights.