Rerversed luminance connecting Sony TV to DVD

[PaulQ]

My Ma and Pa have a 20 year old Sony Trinitron TV (model number KV-2705UB)
that works just fine. They have had a VCR for ten years but always connected
via the RF connector. For Xmas we bought them a DVD and we have had
difficulty getting a picture via the recommended connections for a VCR in
the original instruction booklet: a BNC video connector and a very rare Sony
8 pin DIN (a Sony forerunner to SCART). The major problem is that I am able
to get to get the chrominance to display correctly on the TV but the
luminance is always reversed, see pics here
http://www.fourbridges.plus.com/luminance . For the connection from the DVD
we are using the Yellow DVD composite connector RCA>BNC via a one piece
cable. Audio is no problem because this can be dealt with separately. I'm
writing from the UK so I'm talking about a PAL TV here.

I have also tried out a Hi8 Camcorder on the cable>BNC into the TV with the
same reversed chrominance displayed on screen. On my home TV the DVD shows
correctly both via a SCART-in and via the yellow composite RCA>RCA
connection.

I have been on to Sony customer service and they were unable to give me a
workable solution but they did provide me with a section of the wiring plan
for the TV that confirmed that the 8 pin DIN and the BNC shared the same
circuitry for the GND (pin 6) and the signal carrier (pin 8 - centre pin).
This was a relief because the Sony 8 pin DIN seems to be extemely hard to
find.

If possible, I want to avoid putting the signal through the aerial
connection (I would need to get an RF modulator in any case) due to the poor
picture quality, but I am now out of ideas as to the root of the problem and
what I should try next.

Any ideas?

Thanks

PaulQ

 

[Stan]

}My Ma and Pa have a 20 year old Sony Trinitron TV (model number KV-2705UB)
}that works just fine. They have had a VCR for ten years but always connected
}via the RF connector. For Xmas we bought them a DVD and we have had
}difficulty getting a picture via the recommended connections for a VCR in
}the original instruction booklet: a BNC video connector and a very rare Sony
}8 pin DIN (a Sony forerunner to SCART). The major problem is that I am able
}to get to get the chrominance to display correctly on the TV but the
}luminance is always reversed, see pics here
}http://www.fourbridges.plus.com/luminance . For the connection from the DVD
}we are using the Yellow DVD composite connector RCA>BNC via a one piece
}cable.

Hmmm...what happens when you connect the Video-Out from the VCR to the
TV video-in? A normal picture or the same problem?

Stan.

 

[Jerry Greenberg]

This is a video compatabilty problem. I am not directly familiar with
the TV model you have, but I think that this connector is really for
some dedicated Sony products to go with the set. I am trying to think
back here...

Considering the age of the set, it may be time to keep up with the
times, and get a more modern set that would be option compatable for
the new technology you want to start to use. You are dealing with a
very old set that was not designed to do what you want it to do.
Infact, the pix quality on the new sets is far beyond the set you
have.

It is possible to fix the problem, but it would take some custom video
amp design, and construction. The cost would be prohibitave for you.

Jerry G.

 

[PaulQ]

Hi Stan

Well with one of the DVDs that they own it is just about watchable with
luminance/chrominance in the correct places but the others (due to stronger
Macrovison, perhaps) are unwatchable. But the real answer that you want
regarding the VCR's comb filter (something I've been reading about, I'm no
expert) is that it does put the chrominance/luminance into the right places.

PaulQ

 

[PaulQ]

Hi Jerry

I apreciate that all that you say is correct and good advice but this is
really where we came in: my parents are in their 70s/80s and are happy with
their TV for daily viewing. I'm probably unable to do major rewiring inside
the box but we would like them to be able to have a DVD player for some
movies plus home-made DVDs and VCDs of family events. Ultimately I may just
have to take the RF route but I would really like to avoid this if at all
possible.

On the Sony connector, if you're interested, there is a wiring diagram at
http://www.whatvideotv.com/articles/hardware/images/200102_scart_4.gif
but Sony have confirmed that the BNC connector coveres the same internal
circuit as Pin6 and Pin8 on the 8 pin DIN.

?

PaulQ

 

[Stan]

}Hi Stan
}
}Well with one of the DVDs that they own it is just about watchable with
}luminance/chrominance in the correct places but the others (due to stronger
}Macrovison, perhaps) are unwatchable. But the real answer that you want
}regarding the VCR's comb filter (something I've been reading about, I'm no
}expert) is that it does put the chrominance/luminance into the right places.
}
}PaulQ
}
}> Hmmm...what happens when you connect the Video-Out from the VCR to the
}> TV video-in? A normal picture or the same problem?

I asked the above question to verify that the TV does, indeed, present
a normal picture when fed from the video in, and I was proposing that
you test this with the VCR (if you already haven't done so).

Stan.

 

[PaulQ]

Hi Stan

I'm not sure if I have put the VCR into the BNC, I probably did, but my main
test for the BNC connector was my Hi8 camcorder. The camcorder via RCA>BNC,
like the DVD, showed the reversed luminance on the TV. In fact, with the
camcorder showing a picture on the TV, I was able to use a check-patterned
scarf with black squares to confirm the chrominance/luminance situation.

?

PaulQ