S-Video is Y/C, so it should be possible to go directly to Y/C. On the 1084 this would be labeled "Luma / Chroma," where one of those inputs also accepts composite under the obscure term "CVBS."
I had one of the non-S models with, IIRC, a couple DIN connectors and a DB9 just for TTL/CGA; on those I believe you could also input Y/C on one of the DINs depending what cables you had lying around and which 'input' you wanted your source to be on the front switch.
