I have "broken" the sound on my partner's iMac

[Crunchie7]

Please can anyone help. i tried to use a cable to transfer old cassette tapes from my hifi to my partner\'s imac. Now it has no sound. I understand after much googling that there is no sound card on an iMac, just part of the mother board, and I have blown it up. There is no beep on startup, and System Preferences states no input or output devices are found.
I realise it would need a new motherboard to fix it properly, which would cost nearly as much as a new computer. But I found a suggestion that a firewire external sound card might be possible.
Can anyone tell me if this is true, and what to buy if it is. Nothing fancy, just sound capability. I don\'t have any idea how it would work, or whether the external sound card has it\'s own speakers and microphone. The suggested product was Griffin FireWave External 5.1 Sound Card for Mac. Or is the computer not capable of using it now I have damaged the mother board /
The computer is a 2007 iMac, running Mac OS X 10.4.11
I would be very grateful for any advice as I am obviously in big trouble ! I was using free Audacity software, and nowhere were there any warnings that i might cause damage.

[jonathan]

Hi
Look in applemenu>System Preferences>Sound
then check what the outputs are set to
also at a basic level check the sound is on and not muted, and the volume is up, connect some headphones to see if anything comes out.
To make the analogue to data conversion did you install any software on the mac that may have grabbed the sound, obvious examples are products such as \"sound flower\" though there are many more.

[Crunchie7]

Thanks for your reply. System Preferences says that there are no input or output devices installed. The volume bar is therefore greyed out.
The only software I installed was Audacity. The computer was ok until I turned up the volume on the hifi. Someone who works for Apple has told me that is what caused the damage. The optical out socket has a red flashing light in it now.
By the way, when googling the problem I did find advice on resetting the optical output port, which I tried without success.
I am fairly sure the motherboard is damaged as there is no start-up beep. But I don\'t know if that would mean an external sound card won\'t work.

[jonathan]

You may of course have damaged the MB, but if so thre would be liekly to be more far reaching problems.
Did you instal LAME with audacity
If you go to the apple menu and \'About this Mac\' click the more info button, then go to Hardware and highlight Audio, what does it say can you upload a screen grab of this?

[jonathan]

Try this:
To use the Mac OS X audio drivers:
Open Audio MIDI Setup (in Utilities folder) and click the Audio Devices tab.

Choose Default Output: Built-in Output and System Output: Built-in Output from the pop-up menus.

Then set audio output to 44.1kHz 2-channel 24-bit
Under Properties for: select Built-in Output.

Set the Audio Output Format to 44100.0 Hz. 2ch-24bit

Quit Audio MIDI Setup.

[Crunchie7]

I have uploaded a screen shot as you requested, and another of the Audio Midi Setup. As you can see on the second one, the computer thinks it has no Audio, all the settings are greyed-out, and nothing can be changed.
Perhaps we will just have to live with the problem.
But many thanks for trying to help
[attachment=553,3] [attachment=553,4]

[jonathan]

Ok lets try a couple of last ditch things:
1. fix permissions using the disk utility found in the Utilities folder,
2. Run the software update to get al software up to date
then restart.
after restart
Try plugging in a set of headphones and see if you get sound. If you do, unplug them and see if the issue is resolved. Or plug in the cable you used to make the sound transfer and take out again.
If not, try resetting the SMC.
1. Shut down the computer.

2. Unplug the computer\'s power cord.

3. Press and hold the power button for 5 seconds.

4. Release the power button.

5. Attach the computers power cable.

6. Press the power button to turn on the computer.

[Crunchie7]

I have worked through the list, but no luck. No-one else seems to have the same problem - I can find lots of stuff online about the red light being stuck on in the optical port, but none of it flashing.
Thanks for trying to help. It looks like it is not fixable.