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Interface PHA2037-mini project - PAL RGB SCART for EU 6-pin TI-99/4A

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Posted (edited)

Hello,
TI99iuc.it and facele.eu togheter to rebuild with optimized dimensions the PAL RGB on SCART interface PHA2037.

a working prototyope v1 is already here and seems to work great!

the PHA2037 interface/Converter is used to convert the video signals from Component (Y/Pb/Pr) to RGB (Scart Standard).

This interface PHA2037 RGB was in origin designed at Texas Instruments in Nice (France) and then assembled in Italy at the Rieti facility.
while in Italy all TI-99/4A computers was sold with an RF modulator, in France only them was distribuited with this PHA2037 RGB SCART interface.

885082888_PHA2037InterfaceRVB-SCART-Topside.thumb.JPG.a44c8c9bdc74fdd09531549ce4d19407.JPG  PHA2037-open.thumb.jpg.3b839b886b064be6af7aa3b9f2afeed0.jpg

 

 

studying the original interface, with the help of Fabrizio (from facele.eu website), is almost born the PHA2037mini interface.

 

736140611_FOTO1.thumb.jpg.3c9f474de7d0f72f38468c3bff2f3711.jpg  845671766_FOTO2.thumb.jpg.e9c2c340177f0d81c92894a515906937.jpg

 

this is a picture of the prototype assembled and working

 

IMG-20190817-WA0014.thumb.jpg.8e8dc037aa0f027cab60492d50458690.jpg

 

Best image is always on CRT Monitor/TVs, LCD ones are compatible of course but quality images depend on the brand of the LCD.

 

the goal would be to have at least an exact copy of the PHA2037 on SCART but with just a small plastic and lighter box on the cable, not like the original one.

 

PHA2037mini could be useful for who missed a video cable and/or want something better of the Composite or RF signal and search something not expensive but 100% compatible to solve the problem.

if you are interested in it keep in touch!  this thread will be updated time by time.

 

Ciro and Fabrizio




 

Edited by ti99iuc
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Posted (edited)

The schematic look the message  Septembrer 2010

 

 

Edited by humeur

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When I think it's been since 2010, that I write that the French system by the scart is really better than the Pal sytem. and it's 9 years after we thought I was right

 

Attention works only on euro hardware, easy to recognize TI 99 /4a 6 pins DIN video plug

 

 

Quand je pense que cela fait depuis 2010, que j'ecrit que le system Francais par la prise peritel est vraiment mieux que le sytem Pal

et ç'est 9 ans après que l'on se dit que j'avais raison.

 

Attention fonctionne que sur le matériel euro, facile à reconnaître la fiche DIN vidéo de TI 99 / 4a  à 6 broches.

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There is another schema with a Harris component difficult to find HAI 4625

A quadruple op amp, the result is the same as with the LM318.

And yes I have at disposal a PHA 2037.

 

Il existe un autre schéma avec un composants Harris difficile a trouver HAI 4625  https://www.alldatasheet.com/datasheet-pdf/pdf/907052/HARRIS/HA-4625.html

Un quadruple ampli op, le résultat est le même qu'avec les LM318.

 

Et oui j'ai a disposition un PHA 2037.

 

 

 

 

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Hi,

 

I am interested on one PHA2037 mini  !

 

I‘m using a PAL console.

 

Wolfgang (wolhess)

 

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Great idea, will there be some work in progress updates to show on here and what price are you looking to sell them for?

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Posted (edited)

Yes OX, once the the prototype will become 'final' we will have a better complete idea for costs to sell them. i will update this thread with all news.
thanks for your interests :)

Edited by ti99iuc

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One flaw of the original PHA 2037 was that it is missing a certain signal on Pin 16 to tell the display that a RGB signal is send instead of a Composite signal. I think it is also called RGB Enable Signal. Afaik Pin 16 requires 1 to 3 Volt to enable RGB signal mode. Therefore with the original PHA 2037 you need a display which can be set into RGB mode by you.

Integrating this into the design would enhance compatibility with Displays greatly.

You will not have this problem on a RGB monitor, you will not have a problem if you can set your TV into RGB mode manually, but without the right voltage on Pin 16 a neutral display correctly assumes a composite signal is coming and therefore deals with the signal from the other pins different to draw the picture, resulting in not the desired picture.

 

This remembers me on searching for a dedicated Display for the TI-99 around 2011 at the Media Markt, bringing the bare Console with Power and the PHA 2037 and asking the employees to test it with their TVs and Computer Displays. It was fun for them to see Donkey Kong appearing on their hyper modern TVs. Back then I didn't knew about this flaw in the RGB modulator and thought most TVs are simply bad.

 

With a compatible display the TI-99 PAL really shows offs a high quality picture. This is miles ahead of a composite output the TI-99 NTSC console offers you. This is more than miles ahead of the PHA 3026 PAL modulator, which modulates the signal from low frequency to high frequency to show up as a TV channel for a PAL Tuner. This is very close to the picture quality the F18A provides. The reason is the different Video chip in the PAL console. The 9918A used in the NTSC version has a pin where it outputs composite video signal. This is not existing in the 9929A used in the PAL version. On the 9929A there are 3 pins, every of these pins contains a part of the video signal: Y, Yb, Yr. This means you start off with a much clearer, interference-free picture.

 

A second recommendation would be to handle the situation where one wants the audio to be going with Scart to the display, but also the other situation where one wants the audio to be going to a dedicated device and the audio signal not even forwarded to the Scart output to avoid interferences. I assume the input for the PHA 2037 mini is the 6pin DIN.

 

Once you are ready to take orders, ensure to inform RetroRGB to spread the news on this device:

https://www.youtube.com/channel/UCLPIbBCKVH2uKGm5C4sOkew

 

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2 hours ago, kl99 said:

One flaw of the original PHA 2037 was that it is missing a certain signal on Pin 16 to tell the display that a RGB signal is send instead of a Composite signal. I think it is also called RGB Enable Signal. Afaik Pin 16 requires 1 to 3 Volt to enable RGB signal mode. Therefore with the original PHA 2037 you need a display which can be set into RGB mode by you.

Integrating this into the design would enhance compatibility with Displays greatly.

You will not have this problem on a RGB monitor, you will not have a problem if you can set your TV into RGB mode manually, but without the right voltage on Pin 16 a neutral display correctly assumes a composite signal is coming and therefore deals with the signal from the other pins different to draw the picture, resulting in not the desired picture.

 

This remembers me on searching for a dedicated Display for the TI-99 around 2011 at the Media Markt, bringing the bare Console with Power and the PHA 2037 and asking the employees to test it with their TVs and Computer Displays. It was fun for them to see Donkey Kong appearing on their hyper modern TVs. Back then I didn't knew about this flaw in the RGB modulator and thought most TVs are simply bad.

 

With a compatible display the TI-99 PAL really shows offs a high quality picture. This is miles ahead of a composite output the TI-99 NTSC console offers you. This is more than miles ahead of the PHA 3026 PAL modulator, which modulates the signal from low frequency to high frequency to show up as a TV channel for a PAL Tuner. This is very close to the picture quality the F18A provides. The reason is the different Video chip in the PAL console. The 9918A used in the NTSC version has a pin where it outputs composite video signal. This is not existing in the 9929A used in the PAL version. On the 9929A there are 3 pins, every of these pins contains a part of the video signal: Y, Yb, Yr. This means you start off with a much clearer, interference-free picture.

 

A second recommendation would be to handle the situation where one wants the audio to be going with Scart to the display, but also the other situation where one wants the audio to be going to a dedicated device and the audio signal not even forwarded to the Scart output to avoid interferences. I assume the input for the PHA 2037 mini is the 6pin DIN.

 

Once you are ready to take orders, ensure to inform RetroRGB to spread the news on this device:

https://www.youtube.com/channel/UCLPIbBCKVH2uKGm5C4sOkew

 

and already Klaus ..... the "RGB Blanking" enable I entered it, as for the audio, there will be an RCA connector in the box from which to take the AUDIO signal.

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Sorry to contradict you pin 16 does exist and on the diagram I give it receives a voltage via a resistor.

 

If some research this PHA2037 I have someone in exchange possible.

 

 

Désoler de vous contredire la broche 16 existe bien et sur le schéma que j'ai donner celle ci reçoit une tension via une résistance.

 

 

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Hi 🙂
Pretty project!

My TMS9929A to RGB converter (the one I have made for my TIny-99/4A computers) has a different approch. It only use some  NPN transistors, resistors and caps. It's footprint is tiny too: about 3/4 the size of a credit card.

Edited by fabrice montupet
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1 hour ago, fabrice montupet said:

Hi 🙂
Pretty project!

My TMS9929A to RGB converter (the one I have made for my TIny-99/4A computers) has a different approch. It only use some  NPN transistors, resistors and caps. It's footprint is tiny too: about 3/4 the size of a credit card.

Transforming the YPBPR signal into RGB is only a sum and level difference, which you can do with transistors, but even better with the op amps ...

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6 hours ago, Sid1968 said:

Seeing is believing ;-)

Yes! And it's my way of life 🙂

Sorry about the poor lighting of the video, I made it 30mn ago, it is 9:25PM here and I used my smartphone. But this already can give an idea of the possibilities of my tiny converter:

http://www.ti99.com/misc/RGB.mov

I am right-handed and I Held the smartphone with my right hand, on the video you can see that I can not do anything with my left hand, even turning on a switch! LOL

If you want, I can redo a video this weekend, in broad daylight. A result is even better.

 

6 hours ago, fabrizio said:

Transforming the YPBPR signal into RGB is only a sum and level difference, which you can do with transistors, but even better with the op amps ...

You're right, choosing Op amps is a very good solution. My eyes have 53 years old, may be it's the reason but I don't see any difference between pictures generated by my PHA2037 converters and the one I made using NPN transistors.

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Thank you. If i understood it right your mod is onboard and you go with YPbPr to your Monitor? Would be interesting how it looks on a LCD-Monitor.

Maybe you should start your own thread not to get offtopic. There you should describe you project more detailed.

Edited by Sid1968

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I just wanted to congratulate Ciro and Fabrizio for their pretty board and say that they took a different way to make a RGB converter. And I found it interesting. No more. Even the result is also good, I don't use LCD monitors with the converter, only CRTs. My converter generates RGB signal from the 9929A VDP, it is just a part of the bigger project, I will no make a thread for that.

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But the 6 Billion Members of this forum would be interested in... ;-)

BTW... is it possible to buy one of your PHA2037?

Edited by Sid1968
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16 hours ago, fabrice montupet said:

I just wanted to congratulate Ciro and Fabrizio for their pretty board and say that they took a different way to make a RGB converter. And I found it interesting. No more. Even the result is also good, I don't use LCD monitors with the converter, only CRTs. My converter generates RGB signal from the 9929A VDP, it is just a part of the bigger project, I will no make a thread for that.

 

18 hours ago, fabrice montupet said:

I just wanted to congratulate Ciro and Fabrizio for their pretty board and say that they took a different way to make a RGB converter. And I found it interesting. No more. Even the result is also good, I don't use LCD monitors with the converter, only CRTs. My converter generates RGB signal from the 9929A VDP, it is just a part of the bigger project, I will no make a thread for that.

We congratulate you .. Just take a look at your website!
Our projects are born mainly for ourselves, for passion and experimentation !

Grazie Mille !

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There's mentions above, but does anyone have access to the schematics/PCB diagram for one of the euro Ti-99 modulators they could send me (or a link to)?

On 8/28/2019 at 12:07 PM, fabrice montupet said:

My TMS9929A to RGB converter (the one I have made for my TIny-99/4A computers) has a different approch. It only use some  NPN transistors, resistors and caps. It's footprint is tiny too: about 3/4 the size of a credit card.

I have a PHA2036 which I'd love to modify to analog RGB or even make up something from scratch if anyone has any information on how to do this - a simple circuit using NPN transistors as mentioned above sounds perfect for me....

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