On Dec 4, 3:42*pm, Berend wrote:
All,

i've here a Mitsumi MDF8-UE3681 RF modulator that with some help
fromhttp://ask.metafilter.com/56826/now connects an old DVD player to
an
even older TV set.

But the picture is negative.

The modulator has 4 pins, 3 potmeters, a switch, coax in/out, and a
cinch connector at the right.

The pins are marked: BS, V, A and B.

A and V is connected to Audio and Video signal.
BS connects to +5v
The a/v shielding and chassis go to GND.

(1 potmeter controls the channel, 1 ferrite core does something
with
audio, and the last is a dragging one that does some w/the video.
The
switch seems to be for a testpattern with two vertical bars?)

Berend

Are you _certain_ that the modulator requires sync negative? I've
never seen one but it's conceivable to build a modulator that requires
sync positive. It's not like audio where the absolute phase doesn't
matter. (OK some audio nuts swear they can tell the difference but
most of us can't).

G²