IBM 5150 Hardware Maintenance Manual page 22

When an IBM Personal Computer is powered on, the
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normal responses are:
1. A cursor appears on the display in approximately 4 seconds.
2. One short "beep" after the POST.
3. The "IBM Personal Computer BASIC" and copyright
statement on the display. (If the Advanced Diagnostic
diskette is loaded, the first diagnostic menu should appear
on the display.)
When a failing system is powered on, there may be one or
more of the following responses:
1. Audio error responses (Beeps).
2. Error Co'des (101,301, etc.).
Note: These error codes may appear for only a short time
at the end of the POST.
3. Blank or incorrect display.
Position the System Unit Power switch to Off. Wait 5 seconds
and position the power switch to On. Make a note of all
failure symptoms.
CONTINUE
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