What sort of 1084S accepts UHF modulated input? I ask as I know, for a 100% fact, that mine did not.
If you have one the same as mine was, then you can select CVBS (composite video/blanking/sync on one cable, yellow plug) or L/C (two cables, yellow and black plugs) with a switch on the back. If the switch is set for L/C then you will not get colour through the CVBS input, as that channel will only be carrying Luminance and you will not have anything connected to the Chrominance input.
A1200 composite output is quite reasonable, but RGB is so much better - it is worth the cost of a proper cable (imo).
