RGB to SCART Display Problem

jjc001 · electronics forum beginner Joined: 12 Jul 2006 Posts: 3

Hi

I have an amplifier with RGB and Sync Phono connectors and I am
connecting this to a scart equipped TV. (Input from source DVD player
goes to to the AVAMP and then routed to TV from the AMP). I am
receiving an image on the TV when I select the scart to be in RGB mode
but there are some flickering lines on the screen. This is not the
whole image flickering (as happens if I disconnect the sync cable) it
is multiple (single pixel) flickering lines going horizontally across
the screen.

I have independently disconnected each RGB cable (obviously this
changes the colour of the image) to see if it is either of these cables
but the lines remain. If I disconnect the sync cable the image is
completely unstable as would be expected and therefore I cannot tell if
the lines remain.

If I connect SCART to SCART from DVD to TV in RGB mode then the image
is fine.

If I connect SCART to S-video (DVD to AMP) and s-video to SCART (AMP to
TV) image is fine.

If I connect SCART to S-video (DVD to AMP) and RGB+Sync (Phono) to
Scart) (Amp to TV) - AMP does conversion from s-video to RGB - I get
the flickering lines.

Does anybody have any idea what may be the cause of these flickering
lines or at least how I might diagnose them. Could it be bad shielding
on the cable, a missing pin connect, bad grounding?

Thanks in advance.

René · electronics forum beginner Joined: 22 May 2006 Posts: 2

On 12 Jul 2006 02:54:15 -0700, "jjc001" <jj.chamberlain@ntlworld.com>
wrote:

M.Joshi · electronics forum addict Joined: 02 May 2005 Posts: 51

Usually the leads that have extra sync. connectors are for Plasma
screens and projectors that supports component input.

I think you just need a standard SCART -> 3 RGB Phonos?

jjc001 Wrote:

jjc001 · electronics forum beginner Joined: 12 Jul 2006 Posts: 3

Hi René
Thanks for the quick response. Initially I had pins 8 and 16 connected
also (although I still had the flickering lines).

I tried disconnecting these pins (to see if these were causing the
problem) as I can select RGB manually on the TV along with the screen
format (16:9,4:3).

So yes flickering lines were present with/without pins 8,16 connected.

Are these pins mandatory for RGB + Sync?

I thought for RGB then pin 8 was was 16:9 4:3 select (I am doing this
manually) and pin 16 is - I am doing this manually using the TV menu
and pin 16 was RGB mode select again I am doing this manually via the
TV.

Thanks again

John

René wrote:

Dave Plowman (News) · electronics forum Guru Joined: 29 Apr 2005 Posts: 408

In article <1152710553.812872.142570@75g2000cwc.googlegroups.com>,
jjc001 <jj.chamberlain@ntlworld.com> wrote:

jjc001 · electronics forum beginner Joined: 12 Jul 2006 Posts: 3

Hi

Thanks for the advice. I have now resolved the problem. It would seem
that the amp had some settings that indicated it should look for the
source of the signal from the input RGB + Sync feeds when in fact I
wanted to use the up conversion facility of the amp so I input s-video
and composite feeds and output the RGB + Sync to the SCART (ie there
was no feed on the RGB + Sync inputs).

So even though I was getting a picture (with flickering lines) it would
seem that the amp was trying to use the RGB inputs where nothing was
connected.

Anyway once I changed the settings to indicate to the amp there was in
fact no RGB input feeds (just s-video and composite) the flickering
lines were gone. So I have renewed confidence in my soldering/cable
making abilities!

Your input/advice was much appreciated, thanks for taking the time to
help out.

John.

Dave Plowman (News) wrote:

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