Quantar, Quantro and Nucleus backboards, other differences?

[oh2lak]

So what is the main difference between Quantar, Quantro and Nucleus. They share the same physical dimensions and chassis, but is the backplane the same in all three?

I've figured out that the main difference between Quantar and Quantro is the PA scheme, Quantar has modular PA and Quantro has the 'old-style' PA and modular exciter only.

Quantar and Nucleus share similar modules, althought at least PA modules are stamped with different model numbers. Are they the same? Can I use a Nucleus PA with a Quantar?

Is Nucleus power supply similar to Quantar's?

Sorry for many questions, I have only a Quantar service manual available and all three different versions of hardware in near distance.

..
Erik