Verifying The A26 Cpu Assembly; Cpu Assembly Quick Check - Agilent Technologies PSA Series Service Manual

Verifying the A26 CPU Assembly

The A26 CPU assembly slides into the instrument from the rear and
connects to the A25 Motherboard assembly. The GP-IB interface
connector, LAN connector, RS-232 connector, Parallel Interface
connector, and the external VGA monitor output connector are all
soldered directly onto the CPU board. If you want to remove the CPU
assembly from the instrument, several assemblies must be removed
before sliding the CPU out. Refer to
instructions. There is no extender board for the CPU assembly.
The replacement CPU board DOES NOT include the A26A1 DRAM
NOTE
board or the A26A2 Flash memory board. It is important that these
boards be transferred to the replacement CPU board. The Flash
contains all of the instrument firmware, plus any options and option
keywords loaded into the instrument.
If you are troubleshooting a frozen keyboard, start by verifying the A26
NOTE
CPU assembly. If the CPU is found not to be the cause of the problem,
suspect the A2 Front Panel Interface or the ribbon cable that connects
the motherboard to the A2 Front Panel Interface assembly.

CPU Assembly Quick Check

Following power-up, the instrument will perform a boot process as
follows:
Once power is applied to the instrument, the screen will remain blank
for several seconds.
Text begins to scroll by on the instrument display as the instrument
boots from the bootrom. During this time you will see information on
the screen, such as what the primary and alternate boot paths are,
what the keyboard path is, and messages that indicate the autoboot
process has started and the CPU is booting. When the message HARD
booted appears, the instrument has stopped booting from bootrom and
is now booting from the main Flash.
If DRAM is bad, there will be a memory check sum error or size
mismatch. If Flash memory on the CPU is bad, an IPL error may occur
and the on screen message is often "Main menu: Enter Command".
Next, a series of keys appear on-screen and the instrument loads its
operating system. More messages appear which tell you what is
happening during the boot process. During this time the instrument is
looking for LAN connections and checking for a floppy disk in the disk
drive.
Chapter 7
Troubleshooting the Processor, Power Supply, and Display
Verifying the A26 CPU Assembly
Chapter 11 for removal
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