After some long and busy years:

1. Boards set: 

- mainboard PCIe backplane with custom wirings;

- logic analyzer interface 1 (green board);

- CPU + ram buffer + sdcard + serial i/o board (right side of the mainboard);

- Host/drive i/o interface for mainframe/tape drive;

- CPU i/o/isolation buffer - right side.

2. Main board

3. CPU + ram buffer + serial i/o + sdcard i/o (top)

Tape Drive / mainframe interface (bottom). In the square there are some magic incantations written in the language of Dracula (Romanian), it says like this:  "jumpers explained:  function is automatically associated from the corresponding PCIe port. Manual settings are reserved for diagnosis only.  To be drawn: -> table with manually-configuration jumpers; -> all jumpers to be re-named (actually "re-baptized" with a new name)

4. Logic Analyzer interface (top, green)

Isolation buffer (bottom).

Back into the surgery room.

Keep in touch.

[end of transmission]