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3.14.1. What do the error beeps mean?

Tones Meaning
lo CPU board or Memory error
lo, lo Memory failure (no usable memory)
lo, hi Card Cage error (general logic failure)
lo, lo, hi CPU board error
lo, hi, lo I/O board error
lo, hi, hi Memory error
hi, lo, lo Expansion slot error
hi, lo, hi Keyboard error
hi, hi, lo Keyboard/mouse disconnected
hi, hi, hi Startup device invalid/failure
click Basic test passed
click, click Self-test completed
hi Keypress ignored

The triple tones are typically displayed with an icon that indicates the source of the problem, but of course, in the case of some CPU, memory, or I/O board errors, the display will be either dark, random, or flashing.

Source: Lisa ROM, Lisa User's Guide

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