Porsche Cdr-210 installation help needed

[Dai]

I wonder if someone could help me. I have searched all over this forum for related posts but couldn't find anything relate to my problem. I installed the Cdr-210 stereo unit to my 81 930 and the unit works but there is no sound coming out of the unit. I pushed the volume button but it doesn't seems to do anything. Am I supposed to see some kind of volume bars or volume number? I hooked up all speakers and all speakers tested fine. I wonder if I missed something or do I need to set something else up. Everything seems to be fine. Also, the red wire to the ignition positive doesn't seem to work but the yellow wire (permanent positive to the battery) do. I don't know what else is going on. Any help would be greatly appreciated. Thanks.