AT&T PC 6300 - Page 9

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Service Manual
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lOXX—Parallel Printer Tests 4-152
18XX—8087-2 Numeric Co-Processor Tests 4-152
20XX—Mouse Tests 4-153
21XX—8530 Serial Port Tests 4-154
23XX—Video Option Board (DEB) Tests 4-155
24XX—HDU Drive No. 2 Tests 4-167
MAINTENANCE
GENERAL 5.5
Troubleshooting 5.5
Replacing Faulty Modules 5-5
Reminders 5.6
TROUBLESHOOTING WITHOUT SYSTEM
TEST 5.7
System Will Not Power Up Normally '.. 5-7
System Load Check on Power Supply 5-9
Short Isolation Procedure 5-19
Display Check 5-26
Mini-Floppy Disk Unit Check 5-28
Two Mini-Floppy Disk Units 5-28
One MFD Unit and One HDU 5-33
System Will Not Access Hard Disk 5-36
Hard Disk Problems 5-38