98780A Monochromatic Display; 9130K Flexible Disc Drive/Controller Card; Winchester Fixed Disc Drive/Controller Assembly; Bootstrap Loader Card - HP 9020 Service Manual

3-8
Testing and Troubleshooting
98780A Monochromatic Display
This display contains a switch to test internal functions by displaying inverse video blanks which fill
the screen. The 98780A Service Manual contains additional information on offline testing of the
display. Further testing must be done by the DIM or by the system functional tests.
9130K Flexible Disc Drive/Controller Card
A self-test of the drive, drive board, and controller card is initiated on powerup or on SCRATCH
ALL or LOAD BIN. ROM, RAM, and the controller card chip registers are tested. If the tests pass,
the drive access LED on the front panel lights. This indicates that the first part of the self-test has
passed.
The second part of the test requires the installation of an initialized disc. This test reads ID fields
from the disc and seeks various tracks on the disc. If the second part of the self-test passes, the
controller card LED turns on and off once.
In addition to LED indication of self-test status, detailed information is available to the operating
system. The STSC reads the information and displays the results. The STSC also verifies
110
bus
integrity from the lOP to the controller card via loopback circuits on the controller board.
The media initialization routine provides another valuable self-test. Both writing and reading are
necessary to verify the media. The drive and the controller card are verified by this process.
Winchester Fixed Disc Drive/Controller Assembly
The controller assembly consists of an
110
card and controller board. The self-test is initiated at
powerup or on a SCRATCH ALL or LOAD BIN. The
110
card is tested first. The test begins by
verifying the internal operations of the 8039 microprocessor including internal RAM. Then the
8039 timer is tested. If successful, the 8039 then tests the message and control registers followed by
the control logic for the FIFO buffers. Data patterns are then written to and read back from the FIFO
buffers, ensuring data path integrity. Finally, a checksum is performed on the boot load ROM.
The controller board is then instructed to initiate its own internal diagnostic and RAM sector buffer
diagnostic. The controller assembly then waits up to 19 seconds for the fixed disc drive to spin up
and indicate "ready" status. The drive is then recalibrated to track 0 and the maintenace informa-
tion is read from the maintenance track.
If the drive LED fails to go on, the controller assembly failed self-test. If the drive LED goes on,
indicating the drive is being accessed, but the controller assembly LED fails to go off, a bad drive is
indicated.
Bootstrap Loader Card
The LED on the card indicates if the data in the loader ROM was correctly loaded to the system
RAM. The LED goes on at system reset and goes off when FR1 is written with bit 7 = O. If the LED
goes on and then off, the bootstrap loader code has been properly downloaded to the system RAM.
If the LED fails to go off, the code has failed to load properly. This could also indicate an error in the
code which directs the device to be disabled. A data transfer error would not disable the board, and
the LED would go off.
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