[Kenwood] need advice on kenwood twins 599a

[yash at aol.com]

 Have a 599a  receiver,loosened and removed the 2 set screws from the main tuning knob. can not get the knob off the shaft its attached to. figured may its gulled up on the shaft or corroded somehow.put a few drops of pen. oil down the screw holes,let sit for 1/2 hour ,no luck. There is nothing in the service manual about how the dial,gear assembly is put together,or comes apart. don't want to do damage to anything. Can any body shed some light on this? maybe  this dial assembly  used in another kenwood rig? that its service manual might show how. Thanks for any help.
dale wt4t