IBM Thinkpad BIOS:

Beeps/Error

Description

Continuous beeping

System board failure

One beep; Unreadable, blank or flashing LCD

LCD connector problem; LCD backlight inverter failure; video adapter faulty; LCD assembly faulty; System board failure; power supply failure

One beep; Message "Unable to access boot source"

Boot device failure; system board failure

One long, two short beeps

System board failure; Video adapter problem; LCD assembly failure

One long, four short beeps

Low battery voltage

One beep every second

Low battery voltage

Two short beeps with error codes

POST error message

Two short beeps

System board failure