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TI-99/4A with PAL

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We had a recent discussion about NTSC, and there was a question how the TI looked like under PAL. I pulled my cardboard boxes from the shelves, and there is was - my TI #1, the one from 1982. I was anxiously connecting the power supply and the video cables, as my little console did not see any electrical power since 1984. That year, I bought a second console from last sales, and used that second console until I got my Geneve in 1990.

 

And unbelievable! It still works! Switched on and ... beep!

 

My only issue was that I brought the last CRT television to the recycling collection station (we call it "Wertstoffhof" in German) only a few months ago.

 

However, the Samsung flat screen TV that I currently use with my Geneve still has a analog tuner and an antenna socket, so I tried, and it worked. When you look at the following pictures, keep in mind that this is the impression you get from a today's flat screen TV trying to show an analog input. In fact, I found a mini TV in the cellar, but its screen is too small for good photographs. But the colors were better with CRT.

 

In the third picture you see the console with Parsec running, and the PAL modulator sitting to the right.

 

As you can see, the colors are quite good, some bleeding especially for blue, and white is not so good, has a gray shadow. Apart from that, the picture is pretty much as I remember it. There are a few stripes with varying brightness, but some are photograph artifacts. I added a close-up to prove that they are actually not visible.

 

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One of the main differences is that transmission errors in NTSC lead to hue errors, while in PAL they lead to desaturation. TV sets with PAL never had a hue adjustment. You can see with the above pictures that the stars are almost white (only a very slight touch of color), and the thin vertical lines in the Parsec landscape also turn to white. There are also some color errors on the edges of color fields, but these may be artifacts of the sharpening filter in the TV. Typically, the edges get a little fuzzy.

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And you need 50 Hz AC power.

 

I use an EU power supply with an NTSC console so it must also be possible to use a US power supply with a PAL console.

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Yeah, I knew about the need for a power converter already, I was curious about if I'd need to get a whole new TV to boot. And video cable. Given i'd have to buy and import a console from Europe, I'm not sure it's worth it just for a look-see.

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That's pretty sharp, all right! I never got to see a PAL unit run either. It's nice to see the colors so clear - I almost think that the fringes on white and black are more ringing than hue corruption. Certainly nice to see!

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And you need 50 Hz AC power.

 

The frequency is irrelevant surely as it's rectified to DC? What you need is the correct 110V or 220V transformer block (for the console).

 

Or maybe you're talking about the power for the TV rather than the console, where the TV is locked to the mains frequency? You probably are ... ;-)

Edited by Stuart

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The power supply itself seems to be AC/AC, but you're right, inside the console we have DC. I was wondering whether the VDP clock depends on the AC rate, but it is the same 10.7 MHz, but more scan lines for PAL that eventually yield the 25 full frames per second vs. the 29.97 of NTSC.

 

Also, the TV set must be able to synchronize to the 50i.

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So here's another question... let's say you get a PAL TI-99/4a. And you got a transformer so you can convert U.S. power from 60mhz to 50mhz. All good there.

 

COULD you hook up a PEB that is running on 60hz power? Or does the power signature need to match across all peripherals?

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And you got a transformer so you can convert U.S. power from 60mhz to 50mhz

 

 

MHz? The frequency of US mains has gone up rather since I last heard! ;-)

 

The frequency of the mains power that you apply to the console and PEB is irrelevant - it gets converted to DC. BUT you need to use a transformer (power block) matched to the mains voltage - so in the US you can happily power a PAL TI-99 from the same power block that you use for your NTSC TI-99.

 

The TV is a bit different, as it needs to accept a PAL signal. A 'modern' digital TV is probably OK if it says it accepts a PAL signal. But if you're looking at using a CRT TV, older ones used the mains frequency as a timing source. So to use one of these, you'd need a mains power source that was not only 50 Hz, but also 220/240V. You can change the voltage using a transformer, but you can't change the frequency.

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MHz? The frequency of US mains has gone up rather since I last heard! ;-)

 

The frequency of the mains power that you apply to the console and PEB is irrelevant - it gets converted to DC. BUT you need to use a transformer (power block) matched to the mains voltage - so in the US you can happily power a PAL TI-99 from the same power block that you use for your NTSC TI-99.

 

The TV is a bit different, as it needs to accept a PAL signal. A 'modern' digital TV is probably OK if it says it accepts a PAL signal. But if you're looking at using a CRT TV, older ones used the mains frequency as a timing source. So to use one of these, you'd need a mains power source that was not only 50 Hz, but also 220/240V. You can change the voltage using a transformer, but you can't change the frequency.

 

So I don't need to purchase a transformer at all? That's good news! Those suckers are pricier than I thought.

 

As for the TV, I just picked up a monitor on eBay that says it supports both PAL and NTSC. But from what you're telling me, THAT may require a transformer, yes?

 

This is what I got, the 17" model: https://www.accu-tech.com/hs-fs/hub/54495/file-17695823-pdf/docs/v1320-datasheet_en-201001.pdf

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So I don't need to purchase a transformer at all? That's good news! Those suckers are pricier than I thought.

 

As for the TV, I just picked up a monitor on eBay that says it supports both PAL and NTSC. But from what you're telling me, THAT may require a transformer, yes?

 

This is what I got, the 17" model: https://www.accu-tech.com/hs-fs/hub/54495/file-17695823-pdf/docs/v1320-datasheet_en-201001.pdf

 

The datasheet says that it supports 100 - 240V, 50/60 Hz. So it is compatible with both US and UK mains voltage and frequency.

 

Not sure though that a monitor will accept the TV signal output from the TI RF modulator. Might need to pick off a composite video signal to feed to the monitor.

Edited by Stuart

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The datasheet says that it supports 100 - 240V, 50/60 Hz. So it is compatible with both US and UK mains voltage and frequency.

 

Great! I have no familiarity in this area and am deathly afraid of an electrical fire occurring by doing the wrong thing, so I appreciate the help.

 

Also, I'll need a BNC to RCA adapter for the video, this is what I need, right? https://www.amazon.com/Sienoc-BNC-Female-Adapter-Connector/dp/B00KX17NGU/

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So I don't need to purchase a transformer at all? That's good news! Those suckers are pricier than I thought.

 

As for the TV, I just picked up a monitor on eBay that says it supports both PAL and NTSC. But from what you're telling me, THAT may require a transformer, yes?

 

This is what I got, the 17" model: https://www.accu-tech.com/hs-fs/hub/54495/file-17695823-pdf/docs/v1320-datasheet_en-20

 

Guess I can't delete a message

Edited by retiredqwest

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Hmm... looking on the TI Tech pages, the PAL monitor plug is different from the US version. So I'll need a composite cable specifically for the PAL unit, correct?

 

And the lack of a tuner isn't something I had considered... this is why we needed that *EXPLETIVE DELETED* RF Modulator for TV's.

 

What's the best solution here?

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A PAL console would originally have come with a PAL RF modulator which has a female coax IEC socket, and a male-to-male coax IEC lead to connect the RF modulator to the TV.

 

To use the monitor, I think you'll need to pick off a composite signal from within the PAL RF modulator. There are several versions of RF modulator, just to make things more complicated. There are some instructions here (in Italian plus pictures) http://www.ti99iuc.it/web/index.php?pageid=119&pagina=mod_proj1&sezione=4&data=Mod_and_Tuneed. I've got yet another variation of the instructions (in German) that I'd need to scan in as the website I got it from years ago is now defunct. Apersson850 in message #13 above has also modded his RF modulator to provide composite video as well.

 

So it's not straight forward I'm afraid ...

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A PAL console would originally have come with a PAL RF modulator which has a female coax IEC socket, and a male-to-male coax IEC lead to connect the RF modulator to the TV.

 

I have two different ones: one with a female socket, and one with a male. I think the one with the female socket (requiring male/male coax cable) was the older one.

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