Tube Type Color TV Set/Specific Question/Color Killer

Tube Type Color TV Set/Specific Question/Color Killer

Post by Artcur » Sat, 28 Apr 2001 12:19:48



Hi,

   I have a Magnavox tube type tv, chassis number T95XX.
   The color section of this set uses a combination of 6KE8 as the
color killer/ burst amp, and 6GH8 as the color amplifiers/syn
seperator.
    I have two questions, can someone please tell me how this set
knows to turn the color off during a black and white picture. (part of
the analog waveform)
   My problem is that I am getting colored "snow" or flecks when the
picture is black and white. The color control makes no difference, the
color killer control on the back of the set does not help either.
  The 6KE8 is NOS as the 6GH8's.
   Otherwise the picture is rock steady and the color is good with a
normal color picture.

I know this may seem small or trivial, but if this set is developing a
problem, I want to catch it early.

Thanks,
Art

______________________________________________________________________
Posted Via Uncensored-News.Com - Still Only $9.95 - http://www.uncensored-news.com
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Tube Type Color TV Set/Specific Question/Color Killer

Post by Gudul » Sat, 28 Apr 2001 12:48:01


I  dont think u can do anything about it unless u modify ur  tv. If the tv
station transmit the 3.58 Mhz color burst, the killer will not work. Station
are too lazy to shut the burst off, but with computers they could do that
easy.

Same with FM radios or stereo tv, some cheap jerk in those stations transmit
in mono, but to make u think its stereo , instead of buying a real stereo
modulator ,  they just transmitt a 19 khz pilot tone. That's all it take to
make ur stereo light come on on ur receiver, and u think its stereo and its
only mono.

 Every movie maker now think he is Woody Allen and impose on us black and
white adverti***t, video clips, etc..or all green, or all orange, or
oversaturated luminance and color, flashing pictures, etc. . These pictures
are a real pain to look at.

I have color tvs , I want color, the full range. I dont care for those bogus
"artisses" that use black and white.

 Its a bit  like ham radio still using Morse code.

 
 
 

Tube Type Color TV Set/Specific Question/Color Killer

Post by Bill Meacha » Sat, 28 Apr 2001 12:58:03


Quote:

>  Its a bit  like ham radio still using Morse code.

I agreed with you until I hit that last line.
---
Bill Meacham
Vieques, PR
 
 
 

Tube Type Color TV Set/Specific Question/Color Killer

Post by Andy Cuff » Sat, 28 Apr 2001 12:54:09


Quote:

> Hi,

>    I have a Magnavox tube type tv, chassis number T95XX.
>    The color section of this set uses a combination of 6KE8 as the
> color killer/ burst amp, and 6GH8 as the color amplifiers/syn
> seperator.
>     I have two questions, can someone please tell me how this set
> knows to turn the color off during a black and white picture. (part of
> the analog waveform)
>    My problem is that I am getting colored "snow" or flecks when the
> picture is black and white. The color control makes no difference, the
> color killer control on the back of the set does not help either.
>   The 6KE8 is NOS as the 6GH8's.
>    Otherwise the picture is rock steady and the color is good with a
> normal color picture.

> I know this may seem small or trivial, but if this set is developing a
> problem, I want to catch it early.

> Thanks,
> Art

> ______________________________________________________________________
> Posted Via Uncensored-News.Com - Still Only $9.95 - http://www.uncensored-news.com
>    With Seven Servers In California And Texas - The Worlds Uncensored News Source

Even if the color killer isn't functioning, the color control should
eliminate colored snow on B/W broadcasts.  IF you set it to an unused
UHF channel with the color in the normal position, does the kill do
anything?  Where are you even getting B/W signals from?  I haven't seen
a B/W broadcast for as long as I can remember.  Even when a B/W show is
on, they still send a color signal.
--
Andy Cuffe

 
 
 

Tube Type Color TV Set/Specific Question/Color Killer

Post by Randy & Sherry Gutter » Sat, 28 Apr 2001 13:42:18


Quote:

>  Its a bit  like ham radio still using Morse code.


Quote:
> I agreed with you until I hit that last line.

Hey - code's cool - esp. a model 28 pounding it out at 100wpm+ ;>)

nnnn
ryryryry
nnnn
73 gn

best to ya'!
--
randy guttery

A Tender Tale - a page dedicated to those Ships and Crews
so vital to the United States Silent Service:
http://tendertale.com

 
 
 

Tube Type Color TV Set/Specific Question/Color Killer

Post by William Sommerwerc » Sat, 28 Apr 2001 22:43:37


I have a possible solution to your problem. Maybe.

It is my understanding that B&W movies and TV shows are broadcast in color. The reason
appears to be to let the broadcaster adjust the apparent "color" of the image.

If this is correct (and I'm not sure it is) and the color killer does not have
sufficient range to "squelch" the color... QED.

The way to find out FOR SURE is to poke a 'scope in the set and look at the waveforms.
Is the burst present on a B&W signal? If so, you have your answer.

 
 
 

Tube Type Color TV Set/Specific Question/Color Killer

Post by Jeff Goldsmit » Sat, 28 Apr 2001 23:52:46


??? If I remember right, the color killer works off the 3.58MC chroma burst during the
just after the horizontal blanking pulse in the video signal.? If no RF burst is
detected, the signal is black and white.? Something like looking for the 19KC pilot
signal in FM stereo except the reference is only a burst of a few cycles to
synchronize the chroma oscillator.

??? Chances are your chroma oscillator is still running without a signal.? You might
take the crystal out to see if this is the case.

??????????????? Jeff Goldsmith

 
 
 

Tube Type Color TV Set/Specific Question/Color Killer

Post by Jeff Goldsmit » Sat, 28 Apr 2001 23:55:22


?
??? If I remember right, the color killer works off the 3.58MC chroma burst just after
the horizontal blanking pulse in the video signal.? If no RF burst is detected, the
signal is black and white.? Something like looking for the 19KC pilot signal in FM
stereo except the reference is only a burst of a few cycles to synchronize the chroma
oscillator.

??? Chances are your chroma oscillator is still running without a signal.? You might
take the crystal out to see if this is the case.

??????????????? Jeff Goldsmith
?
?

 
 
 

Tube Type Color TV Set/Specific Question/Color Killer

Post by Bill Sheppa » Sat, 28 Apr 2001 23:59:18


It might be well to clarify what the 'burst' signal is. It's the
syncronizing signal that locks the 3.58 Mhz referance oscillator. It
occurs only during the retrace period and rides on top of the blanking
pulse, hence the term "burst".  Then the oscillator "coasts" for the
actual trace period, getting its next 'sync burst' during the next
retrace.  (The 3.58 oscillator, properly synched, then heterodynes with
the 3.58 chroma bandpass signal, modulated in both phase and amplitude,
to feed the demodulators.)  
            Anyhow, the color-killer circuit is keyed by absence of the
burst. If the station is transmitting burst, the receiver sees the
signal with "color on" even though the program may be in B&W.      
            To set the color killer adjustment on the TV, turn color
gain full 'on' and go to a blank channel for pure snow. Then adjust the
C.K. to where the color in the snow just disappars. This is assuming the
C.K. and color gain controls are working normally.
                     oc
 
 
 

Tube Type Color TV Set/Specific Question/Color Killer

Post by Bill Sheppa » Sun, 29 Apr 2001 00:34:16


Quote:
>Chances are your chroma oscillator is still
>running without a signal.? You might take the
>crystal out to see if this is the case.

The oscillator is _always_ running. The color killer works by biasing
the chroma bandpass stage off, shutting off the color carrier before it
reaches the demods.  
            Disabling the oscillator by removing its crystal would have
no diagnostic value.
              Even with the osc. not running, you can still see the AM
portion of the chroma signal when you turn up the gain. It usually shows
up as green, since there is no phase referance to demodulate the other
colors.
                     oc  
 
 
 

Tube Type Color TV Set/Specific Question/Color Killer

Post by William Sommerwerc » Sun, 29 Apr 2001 04:27:15


Quote:

> Every movie maker now think he is Woody Allen and impose on us black and white
> adverti***t, video clips, etc. or all green, or all orange, or oversaturated
> luminance and color, flashing pictures, etc. These pictures are a real pain to
> look at.

You are an artistic reactionary, devoid of taste and insight.
 
 
 

Tube Type Color TV Set/Specific Question/Color Killer

Post by Andy Cuff » Sun, 29 Apr 2001 05:37:36


Quote:

> I have a possible solution to your problem. Maybe.

> It is my understanding that B&W movies and TV shows are broadcast in color. The reason
> appears to be to let the broadcaster adjust the apparent "color" of the image.

> If this is correct (and I'm not sure it is) and the color killer does not have
> sufficient range to "squelch" the color... QED.

> The way to find out FOR SURE is to poke a 'scope in the set and look at the waveforms.
> Is the burst present on a B&W signal? If so, you have your answer.

I doubt you would ever see a B/W broadcast now.  The color killer in
basically uselss now because of this.  If you looked at a true B/W
signal on a color TV with no color killer, you'd see colored snow on top
of the picture because of the lack of a chroma signal.  This was common
in the early days of color, but now all broadcasts are in color because
they have ads and statio logos in color.  A color broadcast of a B/W
program won't activate the color killer because there is a chroma
signal, it just contains no information.  You should only see colored
snow if you turn the color up all the way because of noise in the chroma
signal.  Since you're seeing colored snow on reruns of B/W shows, it's
not a killer problem.  Is it possible that there's always excessive
noise in the color, but you only notice it on B/W pictures?

--
Andy Cuffe

 
 
 

Tube Type Color TV Set/Specific Question/Color Killer

Post by Philip Nasadowsk » Thu, 03 May 2001 09:34:02


Ok, out of morbid curiosity, are broadcasters required to transmit color
today?  Or can they still run in B&W?

--
To email me, remove the XXXX from my address, and replace it with "mail"

 
 
 

Tube Type Color TV Set/Specific Question/Color Killer

Post by Ed Eller » Sun, 06 May 2001 14:33:27


"Ok, out of morbid curiosity, are broadcasters required to transmit color
today?  Or can they still run in B&W?"

Analog stations are still allowed to broadcast in B&W only.