About Atari 2600 composite mod...

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MockyLock
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About Atari 2600 composite mod...

Post by MockyLock » Thu Oct 16, 2008 1:27 am

Hello everyone :)
First of all, I'm french so i hope you will understand everything.
I tried to add the composite signal to one of my Atari 2600.
It's a MODEL NO Cx-2600 AS, it's a PAL Model.

I used this wiring diagram:
Image

I couldn't find the exact components so i used these ones (all in Ohms):
390 for 370
120 for 130
1K for 1K
33 for 33
220 for 220
470 for 450
Transistor BC639 for 2N4401 (it has E,B,C inversion but I was carefull when soldering).

Here is my soldering diagram:
ImageImage

Because it's a PAL model, i couldn't use the spots marked on the pics. I used this spots on the TIA:
ImageImage
it's not the same pins as NTSC ones.

So, i wired all, and it's not working :/ Sound works well so it's the good chip (not the same label as ones of benheck pics).
When, i turn the VCS on, there is a tiny flash light on TV (so there must be some kind of signal but no images...
Do resistor values are important ? I thought that it would only alter colors or lights.

So, my poor VCS is on my desk, the case opened board soldered, waiting for revival.
Please, help me ^^


[EDIT]
Actually, after more tests, it seems that i have the image but with no sync, the screen is always going to top, and image is cut in alternate Z form (i hope you'll understand my explanations :/)
I used pin 2 for CSYNC.
Thanks for helping me :]

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c_mon
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Post by c_mon » Fri Oct 17, 2008 1:33 pm

As you are French(I suppose you live in France), shouldn't your system be SECAM rather than PAL?

Anyway, if you have the book check Atari MLL and solder a wire from "x" to "u"(pin2).

Let us know...

MockyLock
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Joined:Mon Oct 06, 2008 2:14 pm

Post by MockyLock » Sat Oct 18, 2008 11:46 am

Hello c_mon, and thanks for answerin gme.
As you said, it must be a SECAM model.
I don't understand which are this spots "x" and "u". As you told bout pin 2, i suppose that these are pin from TIA chip ?
pin 2 would be "u" ? so which could be the "x" point ?
I apologize if i'm boring you but with all these difference between NTSC and SECAM models, i'm a bit lost :/

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c_mon
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Post by c_mon » Sat Oct 18, 2008 2:26 pm


MockyLock
Posts:11
Joined:Mon Oct 06, 2008 2:14 pm

Post by MockyLock » Mon Oct 20, 2008 1:01 am

Hello
Once again I thank you for wasting some time with me :)
So, my VCS board is absolutely different from the picture you posted.
As i wrote above, spot u is pin 2, isn't it ?
But waht is the spot "x" ? I guess it must be a resistor ? But, because of the difference between board, i don't know which one...
Arrghhh, but why the hell we French do we have this SECAM curse ???

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c_mon
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Re: About Atari 2600 composite mod...

Post by c_mon » Fri May 25, 2012 2:31 am

If you can send here the front and back pictures, it would help..
I TAKE COMMISSIONS FOR CNC-ROUTED CASES AND PORTABLES... JUST P.M. ME!

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