Data General Eclipse Info needed

[Jerry Wright]

I'm trying to id this system I just rescued last month.  It is an Eclipse of some type.
Chip date codes are 1976-1977  The front panel is white with blue paddle switches.The rear panel ID plate says  it's a 8461, SN 4802-142-157. it has Options  4192, 4010, 4042.  it's a 16 slot back plane and was part of a EMI  Cat scan system.
There are 16 boards in this, 9 are DG and the rest my are EMI scanner boards.

Not sure what sales model it is   ie  C330 or C130 or ???
The front panel is trashed, so what are the differences  between the front panels fromother models.
Are there any manuals for this out there ?? 

The back plane has 2 damaged chips.  one has a  74S133 which i understand the other has 20a. if I read it right.  looks to be a hex inverter of some type ??

Any help would be appreciated 
Thanks, Jerry