I need help moding a tv game programmable console with composite.

[Ethaniel]

Hello all.

Lately I had a "great" idea of adding composite video to one of my pc-50x consoles.

the General instruments catalog says that these consoles had the game chip on the cartridge and a ay-3-8615 on the console to add color.

The output of 8615 says it's composite and ends up in the rf modulator which sucks.

I opened a couple consoles i had but none of them had that chip.

The cartridges contained just the game chip.

So i'd like your rf-to-composite guidelines to locate the color signals.

Is there a generic guide for rf modulators i should follow?

Both consoles have a bunch of HEF and LS chips which seems to only contain logic gates.

I could use all the help i can get.

Schematics, pictures, tips, anything

 

[patrickvogt]

I think you already found this document: http://www.pong-story.com/GIMINI1978.pdf. There is a black/white reference implementation for the 8610 (first game) and a reference colour implementation by adding the 8615 after the 8610 (between page 20 and 30).

 

Honestly I think the best way would be to first try to get a working black/white compostie signal either directly by soldering to the game chip on the cartridge (I don't know if you can just combine all the video signals and sync similar to the AY-3-8500, the above document contains a list of all the video signals, I honestly didn't read the text fully) or by following the traces on the game cartridge to the pin connector and then on the motherboard to find a (maybe weak) black/white compatible composite signal.

 

I think if this is working you can then go to the next step and search for the color signal (which should be somewhere "behind" the point where you took the black/white signal).

 

Sorry that I couldn't help you much.

[Ethaniel]

Yeah I already have that PDF.

I definitely don't want to solder anything on my cartridges.

I will try and trace them back to the motherboard as you suggested.

I have already constructed a regular 8500 composite.

It wasn't that hard either although I did have trouble finding a crystal that matched the schematic I followed.

Anyway, if anyone else has another suggestion please feel free to post.

 

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[carlsson]

Perhaps I'm acting silly, but isn't the black cable with two leads going into the silver box the one you want to tap? I assume it has composite video and ground, but perhaps the signal is not of the right quality or strength to work as a composite video signal without further modifications.

[Ethaniel]

I found the composite signal in the rf circuit last night trying each solder. I will post pictures later when I get back from work.

PS: it won't be pretty

 

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[Dennis90]

Did the composite signal work well? And does someone know if i can get a composite signal from this similar console beacuse the RF signal on mine is very poor, It is called like Programmable TV game, Adman Grandstand or Soundic etc.

Seems there are a bunch of cables inside going from the main circuit board to a separate smaller circuit board where the RF cable is sitting, i tested each of those cables and see if i could get a composite signal and i kinda got a signal when i touched the cable seen in the picuture here: http://oi67.tinypic.com/1262y2u.jpg

But everything was quite dark and just grey and i got no color, and there seems to not be one of those ay-3-8615 color chips in the console, but the console does have color tho when i hooked it up through RF. Is it possible to get a nice picture and color from this one through composite? Mabye there are more cables that needs to be combined in order to get a better signal? or? Hope someone could help with this!

And here is the RF circuit board also: http://oi68.tinypic.com/11lspaw.jpg

[carlsson]

Earlier this year I A/V modded my Interton VC-4000. At first I only got a very dark grey image where you barely could see any details. That console has a pot to get a stronger signal, which allowed me to get a dark colour image on an old CRT TV. However even at maximum the signal wouldn't be detected on my LCD, which prompted me to build an amplifier consisting of three resistors 75 ohm, 2.2K and 3.3K, one transistor 2N2222 or equal and a 5V source from the main board. This is a common amplifier used on Atari 2600, 7800 etc A/V mods. After installing this amplifier, I got a nice image on the LCD and even managed to lower the setting of the original pot.

 

It is not unthinkable that the SD-050 systems would need the same kind of amplifier, perhaps adjusted in terms of resistance depending on how strong the signal is to begin with. I think RF modulators are able to modulate a weaker signal than what TV:s generally would accept as composite video. If you haven't solved it yet, perhaps give it a try.

[TheTIGuy]

Did the composite signal work well? And does someone know if i can get a composite signal from this similar console beacuse the RF signal on mine is very poor, It is called like Programmable TV game, Adman Grandstand or Soundic etc.

 

Seems there are a bunch of cables inside going from the main circuit board to a separate smaller circuit board where the RF cable is sitting, i tested each of those cables and see if i could get a composite signal and i kinda got a signal when i touched the cable seen in the picuture here: http://oi67.tinypic.com/1262y2u.jpg

 

But everything was quite dark and just grey and i got no color, and there seems to not be one of those ay-3-8615 color chips in the console, but the console does have color tho when i hooked it up through RF. Is it possible to get a nice picture and color from this one through composite? Mabye there are more cables that needs to be combined in order to get a better signal? or? Hope someone could help with this!

 

And here is the RF circuit board also: http://oi68.tinypic.com/11lspaw.jpg

Just about the "Adman grandstand", its actually a Fairchild Channel F clone called the Adam Granstand, that is an Arcadia 2001 clone pictured not an Adam.

[carlsson]

Necrobumping this thread, the page Patrik's Retro Tech on Facebook posted yesterday images what appears to be a RGB mod for the Soundic SD-050! Very good picture quality.

[slydc]

I'm pretty sure he got the idea from the ITT Graetz-Ingelen Ideal Computer Tele Match Cassette 2 circuit diagram

which shows how the AY-3-8600 (or 8610) is hooked-up with a CD4011 and then amplified by transistors and

outputs to the RGB (with a scart connector).

 

Also, the Magnavox Odyssey 4305 (the AY-3-8500-1 built-in the TV) is connected in this similar way accept that the ball

is connected to the Red & Green giving the ball a yellow color. Same process was done in the early Pong-clones arcades

like Nutting Associates Wimbledon.

 

Heck...you could colorize an Magnavox Odyssey or any Pong clone console by the same procedure.