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mattyb · Mar 21, 2009, 01:38 PM

When my iMac boots, I no longer have the chime. I've booted several times today, and no chime each time. I am doing a full clone and backing up. Disk Utility said that the volume was OK, what other hardware tests can I do?

The reason that I ask here is that if you Google startup chime, you get & million pages about what a pain it is and how to disable it. When I read that it is actually a hardware check, I decided to leave it well alone.

Art Vandelay · Mar 21, 2009, 01:50 PM

Did you mute your sound in OS X? If yes, it also mutes the startup chime.

Art Vandelay · Mar 21, 2009, 01:56 PM

If you didn't mute the sound, just zap the PRAM to reset the sound volume setting in firmware. If you had a hardware problem detected by POST, you'd get a series of tones to indicate the problem.

Radioflyer · Mar 21, 2009, 04:57 PM

You can have my chime.

I can't figure out how to turn it off or even lower the volume ... It'll wake the dead.

seanc · Mar 21, 2009, 05:10 PM

Radioflyer - turn the volume down in OS X and reboot.

mattyb · Mar 21, 2009, 06:00 PM

Sound isn't muted, I can hear music and films for example.

I haven't got the SoundPrefPane thingy installed.

Been backing up just in case, should I be worried? I understood the chime was a sort of 'all hardware is good' announcement.

seanc · Mar 21, 2009, 06:06 PM

Have you zapped the PRAM or reset the SMC?

mattyb · Mar 21, 2009, 06:39 PM

Originally Posted by seanc

Have you zapped the PRAM or reset the SMC?

No, I shall try the PRAM zapping tomorrow; From what I understand (in the last few mins of reading) , resetting the SMC isn't something to be taken lightly - is this a common task to resolve some problems ?

Cold Warrior · Mar 21, 2009, 06:43 PM

yes, it's common

Art Vandelay · Mar 21, 2009, 06:45 PM

And no, resetting the SMC is not a risky thing. Unplugging any modern Mac for more than 15 seconds resets the SMC. The PMU on older PowerPC Macs could be crashed if you improperly reset it.

seanc · Mar 21, 2009, 06:47 PM

In the days of PMU reset buttons, pressing the button too many times could "corrupt" the PMU - I'm not entirely sure on the specifics though.

All an SMC reset is - unplugging the power cord, waiting 15 seconds and plugging the machine back in.

Edit: Art types faster than me

ibook_steve · Mar 22, 2009, 04:08 AM

I thought that on Intel Macs, muting doesn't mute the startup chime. At least it doesn't on my MBP while it did on my 12" PB G4.

Steve

Andrew Stephens · Mar 22, 2009, 05:08 AM

Muting shouldn't mute the start up chime. It chimes before the Mac has loaded the system so any sysprefs are not available at that time.

SMC reset should clear it. I've found the chime to be very hit or miss, particularly on laptops.

mattyb · Mar 22, 2009, 05:17 AM

OK, since I unplugged the iMac to update the MacBook (which I'm writing this on atm), the SMC reset should be taken care of. When the MacBook has finished charging, I'll boot the iMac.

I'm pretty convinced that on the iMac, lowering the sound did not change the chime volume at startup. Hopefully I can verify this when I reboot.

mattyb · Mar 22, 2009, 07:02 AM

OK, no chime even after being unplugged for several minutes.

Did a PRAM reset and the chime is back. Also seems to boot up quicker.

ernesto_a10 · Mar 22, 2009, 11:22 AM

Mmm, hold down Command Option P and R right after you start up the computer; that may help

Art Vandelay · Mar 22, 2009, 12:27 PM

Originally Posted by Andrew Stephens

Muting shouldn't mute the start up chime. It chimes before the Mac has loaded the system so any sysprefs are not available at that time.

The volume level is also stored as a firmware variable. Whenever I have my MacBook muted, I do not have a startup chime.

Type "nvram -p" in Terminal and you'll see the setting in EFI. When muted it is

SystemAudioVolume %f4

Max volume is

SystemAudioVolume t

Since it's a firmware setting, zapping PRAM is the way to reset. Resetting the SMC would only be useful if something else was causing the problem.