No sound from iMac to receiver

imacken

macrumors 65816
Original poster
Feb 28, 2010
1,232
121
Just today, I have stopped getting sound through my receiver/speaker setup via the optical cable on my 2011 27" iMac 3.4GHz i7.
Always worked fine till today.
1) If I remove the cable, I get sound through the internal speakers.
2) I get a red light at the end of the optical cable
3) if I boot into Windows via Bootcamp, I still get no sound
4) my receiver is set to the correct input
5) if I plug headphones into the same socket, the sound works through them OK.
Any ideas?
 

imacken

macrumors 65816
Original poster
Feb 28, 2010
1,232
121
Yep, it's looking that way. Doesn't work when I plug my MBP into the receiver with the optical cable either.
It was an expensive cable too. I'll order another one later and see if that fixes it.
 

imacken

macrumors 65816
Original poster
Feb 28, 2010
1,232
121
One thing though, surely if the red light is showing in the cable, then the signal is getting through.
 

imacken

macrumors 65816
Original poster
Feb 28, 2010
1,232
121
Got a new cable today and it works OK.
Weird. The old one was expensive and fairly new with the red light showing.
Oh well..... thanks for your input.
 

imacken

macrumors 65816
Original poster
Feb 28, 2010
1,232
121
Spoke too soon.
Sound has stopped working after being OK for a few hours.
Going to try the receiver with my Blu Ray see if it works with the optical output.
 

imacken

macrumors 65816
Original poster
Feb 28, 2010
1,232
121
Not looking good.
I tried 3 things:
1) the receiver with my Apple TV using the optical in/out with same cable. Worked OK.
2) headphones in the iMac. Didn't work except after a bit of waggling of the plug in the iMac socket. Even then it was going off and on.
3) analogue lead from iMac to receiver. No sound except buzzing.
It's beginning to look like the Mac is at fault don't you think?
 

jaxhunter

macrumors regular
Dec 14, 2012
117
14
Maryland Eastern Shore
What year is your iMac? The 2009-2011 models had their audio boards and audio ports as separate parts, both separate from the logic board. Not very expensive as I remember.