AV mod for Atari 2600/7800

[omp]

Hello

I have done the simple AV mod for Atari 2600 (6 switcher, 4 switcher & JNR) as well as the 7800. This was done by the simple transistor + 2 resistor trick.

While it isn't bad, I am keen to know if there is a better way that suits PAL consoles. I know about Longhorn's mod board but I believe that is NTSC only.

Does anybody know of the equivalent of Longhorn's mod BUT for PAL consoles?

Cheers Pete

[Mamejay]

I have made one up using a schematic I found on Atariage.
Atari 2600 4 switch.gif
This is for a Atari 4 switch which does not have a CD4050 chip. This can still be used on a 6 switch or JNR. The results are heaps better than the simple transistor mod and works on PAL consoles.
I have a longhorn mod and this is nearly on par with his mod.
If you have a JNR or 6 switch you can remove the CD4050 and just grab the signals from the built in CD4050 chip of the Atari.

[omp]

Thank you for that, I joined up at atariage a day or so ago. I believe the tia pins are different on a pal console? To get composite on that mod, is it a matter of joining the luma/chroma pins together? Thanks again.

[Mamejay]

Composite can be obtained like this
svideo-diag.gif
Here is the PAL TIA pinout
tia_pal.png

S-Video is so much better than composite so if you can find a TV that supports it I highly recommend using that

[omp]

Thanks again for your help. Is the PAL TIA the same across all the Atari 2600's?

Sorry for the questions, haven't had much to do with Atari 2600's. Having said that I have simply AV modified 6 switcher, 4 switcher, JNR and 7800. Been spending most of my times with Sega's and the like.

[MangledLeg]

*Crazy bump*

I've been working on my 4-switch A2600 and haven't tested yet but wanted to make sure - I've used polarised caps on the above mod and have wired it so that the negative pin is on the GND line and the positive pin is feeding back into the circuit. Is this correct or should I swap the polarity around before I switch on my machine to test?

[omp]

I have actually NOT gotten around to this, but if you view the layout daigram there you will see a slight "shadow" on the lower part of the cap. Like a SMD cap this is generally the -ve side.

[MangledLeg]

Thanks for pointing that out omp - hadn't noticed it until you said as much!! I'll go power it up and see what happens :)

[MangledLeg]

Update - everything worked nicely, my A2600 now has an amazing AV output :) Took the time to microswitch mod my A2600 joysticks while I had the iron out, turned out fantastic!!

[omp]

Damn does this mean I have to re-do my JNR?

[MangledLeg]

If the output from my console's anything to go by, I reckon it'd be worth it :) Couldn't be happier with the result.