Faulty Board Isolation; Self Test; Error Messages - Agilent Technologies 4284A Service Manual

3-1 0. FAU LTY BOAR D ISOLATION
When repairing the HP 4284A, firstly you must find the faulty board. This paragraph pro­
vides the i nformation for isolating the faulty board .

3-1 0-1 . SELF TEST

Self tests are the 4284A's special functions used for making troubleshooting the digital con­
trol group. The 4284A's self tests can be categorized into three types, (1 ) power-on self test,
(2) self test selected with softkeys , and (3) self test selected by a bit switch .
( 1 ) Power o n self test
Every time the 4284A is turned on it performs a power-on self test as part of the power
on sequence. The 4284A performs the following self tests at power-on .
•
R O M check sum test
•
RAM RjW test
•
E E P R O M check sum test
If the power-on self test fails, one of the error messages listed in Table 3-1 1 will be
displayed.
Error Message
RAM TEST E R RO R
ROM CH ECK S U M E R ROR NO=XX
SYST E M DATA CSUM E R R OR
COR R DATA CS U M E R ROR
CAL l B DATA CS U M E R R O R
SCA N N E R DATA CSUM E R R O R
Table 3-1 1 . Error Messages
Description
The RAM RIW test failed.
The check sum of one of the programmed R O M s on
the A7 board is incorrect. The RO M n u m be r with this
message is shown on A7 service sheet, SECTION 4 .
The check sum o f the data on t h e SYST E M C O N
page in EEPROMs on the A 7 board is incorrect.
The check sum of the data on the CORR E CTION
page in EEPROMs on the A7 board is incorrect.
The check sum o f the calibration d ata in E E PR O M s
on the A7 board i s incorrect.
The check sum of the correction d ata for the m u lti
correction in E EPROMs on the scanner
(A40) is incorrect.
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