Keysight Technologies Infiniium MSOV 084A, Service Manual

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148 Infiniium V-Series Oscilloscopes Service Guide
7
Theory of Operation
Motherboard assembly
The motherboard assembly provides all system control and interface functions for
the oscilloscope. The motherboard contains a microprocessor, a hard disk drive
interface, ROM, RAM, keyboard and mouse interfaces, connections to the front
panel board, and serial and parallel interfaces.
Pressing the on/off button sends a signal to the motherboard. The motherboard
then signals the backplane assembly, which in turn sends a signal to tell the bulk
12 V power supply to turn on. When the power supply turns on, the remaining
power supplies are enabled and powered on. Then the main FPGA
(field-programmable gate array) on the backplane assembly gets self-configured
from its PROM. Once it is configured, the main FPGA asserts a signal to tell the
motherboard to power up and become fully functional. The following figure
illustrates this system start-up process.
It is common for the motherboard to be revised during the life of the oscilloscope,
so if a motherboard is replaced during a repair procedure, check to make sure it
matches the image on the hard drive. It is important for the hard disk drive image
to match the motherboard. If they do not match, the oscilloscope may not have
the correct Windows software drivers.
The hard disk drive is a high-capacity (480 GB), removable, solid state,
shock-resistant unit that stores the oscilloscope operating system, the
oscilloscope application, compliance application information, calibration data,
other data files, drivers for the boards and oscilloscope, and user data files. The
hard disk drive can also be used to store and recall oscilloscope setups and
waveforms.
Power-up sequence
MOTHERBOARD POWER SUPPLY
BACKPLANE BOARD
ON/OFF
Switch
Supply Sequencers
PS_ON_N
POWER
SWITCH
Bulk_RemoteOnOff +12V
1
2
3
4
FPGA
5