Linn Karik CD transport : "--" is displayed

It’s in Sleep Mode.  There is a Display switch on the back panel.  If the switch is pressed in and power is applied  the Karik will enter sleep mode.  The two dashes will appear after 20 seconds.

Fix. Push the button off.

I tried it and it doesn't work. Maybe the switch stopped functioning...

Probably not.

If not the switch, what else?

Was the Karik powered on when you pressed the switch?  The rear panel switch position must be selected prior to powering on by the front panel on/off switch.  It is an either/or function.

I tried all options. One of them was putting the switch into non sleep mode prior to powering the Karik

I opened the Karik and using an ohm meter I found that the switch dosn't work.
Spraying it with servisol solved the problem. Display is back :-)
 

Nice, you found a simple fix.  My Karik went to the graveyard smoking and stinking.  The Numerik still soldiers on though.