You'll find what you need there. Mainly the pinout:
Commodore 1084d & 1084dS Analog/Digital Connector
9 PIN D-SUB FEMALE viewed at the monitor
_____________
\ 5 4 3 2 1 /
\_9_8_7_6_/
Pin Name Analog Mode Digital Mode
1 GND Ground Ground
2 GND Ground Ground
3 R Red Red
4 G Green Green
5 B Blue Blue
6 I not used Intensity
7 CSYNC Composite Sync not used
8 HSYNC not used Horizontal Sync
9 VSYNC not used Vertical Sync
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of the DB-9 at the 1080/1084 monitor.
What's NOT apparent is that you'll need to wire a 75 Ohm resistor between composite sync and ground at the DB-9 end of the cable to attenuate the sync signal so that the commodore monitor is happy with it.
I built this cable. It works, with the resistor added