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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc.

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Old 22nd Dec 2009, 9:20 am   #1
mattCRT
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Location: Cardiff, Wales, UK.
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Default Picture Roll Problem

Hey guys,
Whenever i run my Atari games system on my TX9, there is a massive amount of picture roll, I know this is adjusted by the vertical hold knob but there is no such knob on the TV, and i think the knob is inside the TV but i'm not sure.
Does this mean mean i have to open the tv up whenever i need to adjust V-Hold??
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Old 22nd Dec 2009, 9:29 am   #2
Heatercathodeshort
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Default Re: Picture Roll Problem

This is only from a distant memory but I seem to remember a problem with the TX9. I believe the Atari has a 60 Hz frame scan frequency and usually 'fits' into our 50 hz system. Again from memory I don't think the TX9 has a vertical hold control. If it has, adjusting it will cure the problem but you will have to twiddle it again on live transmission. I always said the only signal that should be fed into that little socket should be from an AERIAL! This was the start of a television engineers nightmare.
Regards, John.
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Old 22nd Dec 2009, 12:32 pm   #3
cmjones01
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Default Re: Picture Roll Problem

Is it an Atari 2600? I think this existed in both PAL and NTSC versions. If it's producing a picture at all on a UK TV, it's very likely to be the PAL version. There shouldn't be picture roll since the PAL 2600s do use a 50Hz field rate.

However, apparently the game cartridges themselves have to be the right PAL or NTSC version, too, since the 2600's graphics hardware is mostly software-driven:
http://en.wikipedia.org/wiki/Televis...erface_Adapter

Are you sure the cartridges you're using are for the UK market? If not, then I'd expect picture rolling (and funny colours).

Chris
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Old 22nd Dec 2009, 12:41 pm   #4
Dr-Watts
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Default Re: Picture Roll Problem

Quote:
Originally Posted by Heatercathodeshort View Post
This was the start of a television engineers nightmare.
Regards, John.
Hmmm...
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Do you have the scope to be a TV repair man
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Old 22nd Dec 2009, 4:33 pm   #5
mattCRT
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Default Re: Picture Roll Problem

Yes, its an Atari 2600, and yes, only some of the games roll. it isnt labeled on the cartridge if the game is NTSC or PAL so some of the games are probably NTSC. Thanks anyway
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Old 22nd Dec 2009, 4:38 pm   #6
cmjones01
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Default Re: Picture Roll Problem

Quote:
Originally Posted by mattCRT View Post
Yes, its an Atari 2600, and yes, only some of the games roll. it isnt labeled on the cartridge if the game is NTSC or PAL so some of the games are probably NTSC. Thanks anyway
OK, it looks like we've found the problem, then.

There might be a solution: if the TX9 has a vertical hold control inside it (I bow to others' knowledge on whether it does or not) it might be possible to find a compromise setting which works at both 50Hz and 60Hz. This may make it more prone to rolling on poor signals, or as it warms up, or the height may turn out to be wrong at one or both rates, though.

In any case, the 60Hz games will probably have the wrong colours because of the differences in the way the PAL and NTSC 2600s generate colour.
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