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Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment.

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Old 11th Aug 2019, 7:37 pm   #1
CHRIS_F
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Default Texas Instruments TI-99/4A UK PAL Modulator.

Hi All,

A while back I picked up a TI-99/4A from a local antiques store, it was really cheap and I really only bought it because I bought a couple of tape recorders and the guy gave me the computer really cheap, it had the power supply but no modulator (he said he had the modulator but couldn't find it) I kind of knew he wouldn't find it though.

Is there anywhere I can get a PAL modulator? or is there a similar item that might do the job from another computer maybe? I could mod a modulator to composite video if I had one but I'm stuck without it, they never seem to come up on any of the auction sites.

I have read a few people just use a din plug to get component out, I asked Ian at retro computer shack (I use his spectrum RGB-SCART cables excellent quality) but he said the signal isn't exactly compatible with modern tv component and didn't want to make a lead up for it.

What are my options? I don't even know if the computer works yet until I get a modulator.

I'm kind of excited about this computer as I never heard of them back in day I only ever had a Vic 20 and a Spectrum.
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Old 11th Aug 2019, 8:48 pm   #2
GrahamN
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Default Re: Texas Instruments TI-99/4A UK PAL Modulator.

To use a video cable from a UK TI99/4A you need a TV / Monitor that accepts Y, R-Y, B-Y signals - not composite or RGB.

A diagram of the cable connections is at https://atariage.com/forums/topic/19...omment-3971397
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Old 11th Aug 2019, 9:37 pm   #3
GrahamN
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Default Re: Texas Instruments TI-99/4A UK PAL Modulator.

And if your TV doesn't have component video inputs - search eBay for "RGB/CGA/EGA/YUV to VGA" for a converter at about 15

Overall cost about 20 for cable and converter - it may not work, but it's probably a cheaper and easier option than getting a modulator and worth a try in my opinion.
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Old 12th Aug 2019, 12:08 am   #4
SiriusHardware
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Default Re: Texas Instruments TI-99/4A UK PAL Modulator.

Also likely to produce a better picture than composite-over-RF, which is usually the worst option money can buy.

Direct connection to a TV or display which already has a 'component' input would be best of all, as per Graham's post #2, although I'm not sure what Ian meant by the signal not being entirely compatible with 'Modern' component video inputs.
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Old 12th Aug 2019, 6:49 pm   #5
woodchips
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Default Re: Texas Instruments TI-99/4A UK PAL Modulator.

If it outputs a Y signal then surely that can be taken into any mono monitor to give a picture? The U and V are just for colour.
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Old 12th Aug 2019, 8:27 pm   #6
kan_turk
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Default Re: Texas Instruments TI-99/4A UK PAL Modulator.

Quote:
Originally Posted by woodchips View Post
If it outputs a Y signal then surely that can be taken into any mono monitor to give a picture? The U and V are just for colour.
Yes - or a colour monitor (or TV) with composite input - the Y output has syncs - it will, of course, only give a monochrome display but it will allow you to ascertain if the computer is working or not

Best picture quality will be achieved with component (Y,Pb,Pr) or failing that YC (converter needed) - followed in order of increasing grottyness by composite and finally RF

Rgds
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