P.S. 

Some of the cobwebs of memory are clearing.

I remember that I found the non-soldered

Tube socket terminal by removing the cover

And powering the set, then gently thumping

the tubes and etc with the end of a pencil.

When  it "wiggled," I tapped lighter and lighter

until the slightest brush brought-on the 

"wibble wobbles."  The bad joint was on

that tube socket.