fmashockie (your name?)
Reading all your posts and suffering your long video, I conclude:
1/ Step gen works fine , 576 is very likely working.
2/ NO DUT! Attach a transistor to the test fixture (banana plugs and alligator to any old power BJT) to see the curves.
3/ The manual performance tests, and CAL are NOT what you need! You may do more damage than improvement.
4/please find, read and understand:
a/ 576 user manual, 176 and other test fixtures manual
b/ Curve tracer theory and app notes.
See TEKwkiw, W140, BAMA Archive
lots of great info here
https://w140.com/tekwiki/index.php/576fmashockie (your name?)
c/ Buy a bound printed copy of op/serv orig for your SN or Qservice or Artech (?) copy
The PDF , are not good for troubleshooting in general.
4/ DO NOT mess with the harmonica connectors unless you understand the decades old plastic can easily break.
5/ Many old TEK and 576 bugs are due to transistors or DIP ICs in sockets that have oxidized contacts.
6/ The Tekscopes and Tekscopes2 (different) at groups io may be a better resource.
Bon chance,
Jon