Anyone else ever hear the ancient slang for making an unskilled minor adjustment to a
piece of equipment that is malfunctioning in a minor way: "titravate" ?

Nope.

But over here to titivate would be quite common casual speech for 'fixing up', 'mending' or similar context.

Is this just a spelling variant Bill - where'dja find it?

Dear Mav: my father used to say it about such things as second hand outboard motor
with no instruction manual. He was clever with such things. I cannot claim that.