On Fri, 04 Nov 2011 11:26:48 +1100, Sylvia Else
wrote:

On 3/11/2011 3:49 PM, micky wrote:
On Tue, 01 Nov 2011 18:59:27 +1100, Sylvia Else
wrote:

On 1/11/2011 5:54 PM, micky wrote:
Can a tv input signal connection at the input coax connector affect
only the picture and not the sound??


I have a 25" Sharp TV, CRT, that often loses its picture, but never
the sound. (Other than that, the picture and sound are very good.
It's analog and I only use channel 3 and a separate tuner.)

If by "loses its picture" you mean that the picture abruptly and
completely dissappears, with no effect at all on the sound, I'd say "no".

Boy, am I stupid. Ifnore my first answer. I thought you described
the problem here. I thought that was the problem when I first posted.

But in reality, maybe the picture is still there. It's just so dark
often nothing can be seen but little blue and red hyphen-shapped
lights blinking on for an est. 20th of a second, and then bliniking
on somewhere else around the screen. Hundreds of them at any one time.

At the same time, when closed captioning is on, it looks perfect,
white and bright and the letters fully formed.


You said the previous owner of the television was seeing the same
behaviour. Did he also have what is now your DVDR unit connected?

My own exact DVDR? No. He was a stranger who gave the TV to me via
Freecycle. He just said the picture went out peroiodically and he
got it back by moving the cable that went into the TV.

It's not clear what role the DVDR unit is playing here. If it's tuning
an analogue channel,

I have no analogue channels, just over the air channels.

and just frequency shifting it, then the closed
captioning would have to be generated by the TV. In that case, there is
clearly a fault somewhere in the between the TV's own tuner, and where
the closed captioning gets superimposed on the picture.

On the other hand, if the DVDR unit is tuning a digital channel, and
providing an analogue output, complete with closed captioning, then it's
hard to see that there can be anything wrong with the TV at all, with
the problem lying in the DVDR unit, which is, after all, connected to
the other end of the coax that you waggle.

Yeah, but I have 3 other TVs I watch daily that never have problems

The bad one is in the basement, the good ones in the bedroom, the
bathroom, and the kitchen. The DVDR is in the bedroom.and the
bedroom tv gets the signal first. Then the basement TV with the
problem, after after that the signal goes to the kitchen TV which has
no problems.

(There's an amplified splitter that sends the signal to the bathroom
and the bedroom/office, but the computer is broken so I spend a lot of
time in the basement trying to fix it and using a basement computer)


Not tonight, but I recall that sometimes the picture can almost be
seen, like it is night time, with most of it black and maybe part,
maybe the background, very very dark blue or very very dark red,
barely one shade lighter than black. I guess when the real color
isn't blue or red, it just looks like black.

That really sounds to me as if the DVDR unit is just frequency shifting
an analogue channel, and that there's a faulty connection or dry joint
in the video signal path in the TV - a small amount of the signal gets
through by the capacitance of the failed connection.

What I can do to test this is try to watch a movie on the VCR, which
sits next to the DVDR and is connected in parallel by an A-B switch.

I also have a digital conversion set-top box feeding the VCR, so maybe
I'll just watch television via the box/VCR. I'll do that tonight.

Sylvia.

Thanks a lot.