writes:

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).

Composite video has negative sync.

Are you sure the channel tuning is correct?

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