AT&T PC 6300 - Page 338

DIAGNOSTICS
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Bit Position 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Binary Data Written 10 10 10 1010101010 ^
Binary Data Read -10 10 101110101010 _^j
The faulty RAM chip is determined by comparing the binary data
written and the binary data read. Knowing which data bit is
faulty, one can then locate the faulty RAM chip as shown below.
Example:
Data Written in HEX - AAAA
Data Read in HEX - ABAA
00 00 000100000000
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In the previous example, the faulty data bit is bit 8. Therefore, the
bad chip is the eighth chip in the bank. For a layout of the chips H
in each bank, refer to Chapter 5, "MAINTENANCE." I
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4-132
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