Turned out that the 1701 monitor was a composite monitor. Again my mistake. I was a C64 nut but my memory didn't do well.
Few years ago my sis was at her church's rummage sale when she called me and asked if I still liked Commodore 64. She said there boxes full for $15.
I said hell, get it!
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All complete but lacking in software so I sold it for $45.
Memories fade data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
The cable wouldn't have worked with your monitor.You needed a 5 pin to 3 RCA\Phonos data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
That's right, it was stereo sound.
Doubt it back then data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
https://gona.mactar.hu/Commodore/monitor/manuals/1701_Monitor_Users_Guide_NTSC.pdf
Here is the manual looks like separate Luma and Chroma video, plus one audio lead.
Here is the socket the OP has data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
RF Jack - C64-Wiki
Right again. It's the colors that threw me off. Very familiar too, red, white and yellow. Yellow for video and red/white for left/right sound.
Interesting he does have that port. So it's called the RF port.