Update: Solved! Someone pointed me to the “beep” track of the volume control, which was hidden and muted.

Last month I upgraded my ThinkPad R61 to Ubuntu Jaunty. Recently I noticed that I no longer have the beep when taking it on or off of AC power. I don’t know if it has always been missing since it was installed, or if it went away some time after. The beep still happens at all times prior to the kernel loading, so I don’t think this is BIOS or hardware related. The power applet does know when I am on AC power (or not), and seems able to estimate battery life reasonably well.

Anyone had that before?