AT&T 6300 Service Manual page 198

DIAGNOSTICS
The highest level of diagnostic testing is the System Test
Diagnostics. The System Test Diagnostics are also stored on a
diagnostic diskette. The purpose of the System Test Diagnostics is
to provide service personnel with a flexible means of testing
failing/marginal modules and to verify that repaired modules are
operating correctly.
Note: The Menus driven by the diagnostics will use the
term Main Board instead of Motherboard.
Although all versions of the System and Customer Test work with
all versions of the ROM BIOS and MS-DOS, the following
recommendations are made:
1. When testing a machine with ROM BIOS 1.21 (and earlier),
and MS-DOS 2.11 use System and Customer Test versions 2.05
and (earlier).
2.
When testing a machine with ROM BIOS 1.43 (and later), use
System and Customer Test versions 3.18 (and later).
3. When testing a machine with a WD (Western Digital) HDU
Controller, use System and Customer Test versions 3.18 (and
later).
4. Use all System (Overlay Versions) Tests with MS-DOS 2.11 on
a 128-K machine.
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