I picked up a Nova-4 mini at an auction. Just the CPU box, no peripherals.

Part numbers:
Chassis : M0061411 D1882 P T005 12080 R67
NVR Supply : E0470375 D0882 P A005 12074 R26 T005 12429 R30
Backplane : E0502539 D1282 P A005 12072 R10 T005 12073 R10
0 - Supply : E0526152 D1682 P A005 12062 R48 T005 18878 R00
1 - CPU : E0471713
2 - RAM : E0752855
3 - DIABLO: Rianda Electronics Assy No 020000-21H Diablo Disk Controller
5 - SERIAL: E0859602 D0683 P A005 2041 R16 T005 3523 R10
10 - TAPE : Western Peripherals TC120 Mag Tape Controller
12 - SERL : LV0010629 D3883 P A2041 R16 T3523 R10
15 - SMD : ZETACO Model 295 Storage Module Disk Controller

It looks like the CPU and RAM have most of their identification codes cut off.

On the back of the backplane, the following connections are made:
1 - console port
2 - A-Side and B-Side terminators
3 - Two wide ribbon connectors ending in a 50-pin MRAC connector.
There's a hand-written label attached that reads:
Rianda Electronics
AC020075-002X-06
DIABLO SEP 85
5 - 20 pin card edge connector, 5 wires connected (A81, A85, B54, B69, B99 as far as I can tell)
10 - 1 50-pin card-edge connector and 2 26-pin card edge connectors
12 - same as 5
15 - none, the ZETACO has its connectors on the front of the card
16 - two large connectors going to a 100-pin card edge connector.
There is a card that fits this with a hand-written label that reads:
879-0066-000A
Terminator
I/O Board
Rev. A - Term. I/O - 6
5-16-83

On the A-side of the backplane there are some wire-wrap connections
on pins 93-96:
4 : A94 - 5 : A94
4 : A96 - 5 : A96
5 : A93 - 9 : A93
5 : A95 - 9 : A95
11 : A94 - 12 : A94
11 : A96 - 12 : A96
12 : A93 - 14 : A93
12 : A95 - 14 : A95