Weird JVC 503B "RF converter" pinout?

[luRaichu]

I've come across a shiny box that despite calling itself an "RF converter" is actually an RF modulator for a VCR or something. What's strange is that it looks more "modular" than any other VCR modulator I've seen (wink wink), and only outputs on channel 3. Most of these have a switch to change between channel 3 and 4. Also instead of being hardwired to a VCR, the connections are exposed by contacts on the PC board like a computer card. So you can disconnect iwithout desoldering.
All in all it seems to be designed for extreme ease of replacement.






Now, I would like to make use of this box but I don't know the pinout. All I know is that pins 1 and 6 are tied to the metal case (so ground or shield). That leaves 4 possible connections, +12v, -12v, Video in, and RF out.
Since I really have no clue about how this sh*t actually works, and the search engines don't yield thy results, I would appreciate help with identifying the pinout of this module.