Look who I picked up on the way home.
Two more Sega Saturn Sophia development systems.
I started calling them Sophia 2 and Sophia 3.
Both originated from the UK and both arrived needing attention.
At this stage this is simply the initial assessment.
I had not yet established exactly what was wrong with either machine.
The later repair sequence documents two faulty SG4101 units from this group by serial:
H417010070H417010020
Both later came back to life during their respective no-video repairs.
But that answer belongs to the later repair posts.
For now:
two more Sophias.
Because apparently one enormous Sega development box was not enough.