Check this out, setting up a Retrovibe Rick copy. The ferrules were loose, so off come the machine heads for a taping and pushing back in. But underneath check it:
Explains the wonky tuners, a snapped off screw, so they rotated a little, leaving the original holes finished over, the stub wasn’t even filed flat.
Also poked about with a Harley Benton GA5 5w valve head (Epiphone in all but name), belonging to same guy, who’d been having trouble with it: http://atomictangerinemusic.blogspot.com/
Bit of valve swapping identified the trouble, unhappy power valve, easy replace, but left to him to do as the only EL84 I had about was someone else’s Mullard.