Front Panel Assembly - Keysight 90000 X Series Service Manual

Chapter 7: Theory of Operation

Front Panel Assembly

Front Panel Assembly
The front panel assembly consists of a front panel board, on/off board, display
board, touch screen and controller, AutoProbe II interface board for probe power
and probe control, backlight inverter board, front panel connectors, and cabling
connectors for the AutoProbe II interface.
Front Panel Board
The front panel board provides the main user interface to the instrument through
dedicated knobs and pushbuttons. It also provides power and communication
to the probe interface. The front panel board receives power from the backplane
board through a dedicated cable. The communication link to the board is USB
to the motherboard. The on- board USB hub serves the FPGA microcontroller,
the touch screen controller board, and three front panel USB connectors for
peripherals.
Figure 7- 8 shows a simplified block diagram of the oscilloscope front panel.
Figure 7-8 Front panel
On/Off Board
The on/off board interfaces with the motherboard to provide the on/off switch
function, and with the backplane to provide the probe compensation output.
Power indicator LEDs backlight the on/off pushbutton and are driven by the
motherboard. The probe compensation lugs connect to the calibrator output on
the backplane through an SMB connector coax cable. An ESD protection diode
sits on the on/off board, connecting the signal and ground probe compensation
lugs.
AutoProbe II Board
The AutoProbe II board uses an I
132
2
C interface to communicate with the probes.