Question about Krell pre-pro HTS7.1


My Krell has been packed away for several years but now I have dragged it out of the closet.  I am trying to connect the Krell to my iMac via Toslink optical cable but it doesn't seem to work.  Anyone else using the optical feature?  Is there a setting on the front that I am overlooking?  Need Help!!

pushinit

Yes, I can see the red light.  I will have to figure out how to check the sample rate.  Thank you,

Thank you for the responses.  My new idea now is to go from the iMac with optical into a converter to a standard jack configuration and utilize those outlets on the back of the pre-pro and bypass the optical connection.  Sound feasable?