Front Panel And System Control; High And Lowvoltag'e Power Supply; Z-Axis - Tektronix 2212 Service Manual

Front Panel and
System Control
High
and Low Voltage
Power Supply
Z-axis
2212 Service Manual
2212 Block Diagram
The front panel circuit together with the system control circuit controls the
operation of the oscilloscope. A micro processor in the front panel circuit
reads the closure of bush button and rotational switches and the wiper
position of potentiometers. The front panel processor communicates the
changes in front panel settings to the system processor and activates the
front panel LED's as indicated by the system processor. The system proces-
sor processes the information received from the front panel processor and
generates the correct command data strings to control the circuit throughout
the 2212.
The high and low voltage power supply generates the necessary positive
and negative voltages, and the high voltage in one switched anode power
supply stage. The galvanic isolation from the main input accomplished
with a toroid mains transformer, a rectifier bridge and a switch mode pre-
regulator circuit. The post acceleration voltage is achieved in a multiplica-
tion stage.
The Z-axis circuit controls the brightness and focus of the CRT. During the
retrace the display is blanked. The sweep gate signal received from the
sweep generator circuit acts as unblanking signal. The amplitude of the
unblanking signal is controlled by the intensity control on the front panel
and grid bias adjustment.
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