Power-On Self-Test; Memory 200; Diskette Drive 600 - IBM 3270 Maintenance Manual

Introduction
This section explains the three main diagnostic
aids: Power-On Self-Test (POST), diagnostic tests,
and Problem Isolation Charts (PICs). You do not
have to read this entire section on every service
call, but it will be a useful reference until you
understand the use of POST, the diagnostic tests,
and the PICs.
Note: We recommend that you do the POST and
diagnostic tests each time you service the IBM
3270 Personal Computer or add an option.
Power-On Self-Test
POST runs each time power to the system unit is
switched on and takes 13 to 90 seconds,
depending on the amount of memory installed. It
checks the operation of the following:
• Diskette Drive
• Display Adapter
• Distributed Function Communications
Adapter
• Expansion Unit
• Fixed Disk Drive
• Keyboard and Keyboard/Timer Adapter
• Memory
• System Board
October 1984 2-3