Atari 2600/7800 Composite MOD

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rubber_jonnie
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Re: Atari 2600/7800 Composite MOD

Post by rubber_jonnie »

I've never taken my 2600 apart, so have no idea of how much space there is in it.
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800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
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Re: Atari 2600/7800 Composite MOD

Post by exxos »

I thought I would post this here as I've been puzzling over this for the past few hours...

It seems the TIA chip has a different pinout for PAL & NTSC machines. This could be why when I tried my mod originally, it failed miserably as I could have been following a NTSC pinout for the TIA :roll:

It is also clear that the NTSC TIA chip also appears to have stereo audio output, and yet the PAL one does not..

TIA_PAL_NTSC.jpg
TIA_PAL_NTSC.jpg (49.54 KiB) Viewed 5480 times
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Re: Atari 2600/7800 Composite MOD

Post by rubber_jonnie »

Ok, they're quite a bit different :o
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: Atari 2600/7800 Composite MOD

Post by rubber_jonnie »

Ok, so more info here, got the details of a mod for a 2600jr, which is a bit different.

http://blog.tynemouthsoftware.co.uk/201 ... o-mod.html
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: Atari 2600/7800 Composite MOD

Post by rubber_jonnie »

rubber_jonnie wrote: Wed Mar 07, 2018 9:42 am Ok, so more info here, got the details of a mod for a 2600jr, which is a bit different.

http://blog.tynemouthsoftware.co.uk/201 ... o-mod.html
So, I had a crack at this over the weekend, and I've sort of got sound, but no video, however I think my cables are missing a ground somewhere along the line, as I added the cables slightly differently, so I will revisit and see if that fixes it.

Serves me right for diverting slightly and using cables instead of sockets. D'oh.

I'll report back.

EDIT: So I was right about the gound being an issue, now it's sorted, it's all working nicely. Picture is a lot better than via the modulator, though I have kept the parts in case I want to sell it on at a later date.

Need to look at the 7800 next.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
atari030
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Re: Atari 2600/7800 Composite MOD

Post by atari030 »

Good stuff. I have a Jr I spannered playing with video mods a while back. Glad you did this as I needed some motivation to get on to it. I have a vader I put sockets on, wish I had used cables as I hat things that aren't reversible.
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Re: Atari 2600/7800 Composite MOD

Post by rubber_jonnie »

atari030 wrote: Mon Mar 19, 2018 9:13 am Good stuff. I have a Jr I spannered playing with video mods a while back. Glad you did this as I needed some motivation to get on to it. I have a vader I put sockets on, wish I had used cables as I hat things that aren't reversible.
Cool, glad it's inspired you :)

Here's the cable with the can back on, I had to do some bending of the tin, but it's reversible.
I put a knot in the cable for strain relief, and used a small tie wrap through the old tv out holes.
JR.jpg
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Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
atari030
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Re: Atari 2600/7800 Composite MOD

Post by atari030 »

Nice work. How hard was it to get the modulator out? They tend to be soldered to pretty big grounding plates.
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Re: Atari 2600/7800 Composite MOD

Post by exxos »

Nice :)

Do you get any "rolling" effects in the black background colour ? Also can you try pole position and take a clear screenshot ? I saw some vertical blue lines in the "sky" on mine..
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
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rubber_jonnie
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Re: Atari 2600/7800 Composite MOD

Post by rubber_jonnie »

exxos wrote: Mon Mar 19, 2018 12:37 pm Nice :)

Do you get any "rolling" effects in the black background colour ? Also can you try pole position and take a clear screenshot ? I saw some vertical blue lines in the "sky" on mine..
No rolling effects, but I do get a funny ladder effect down the left hand side, but it's off to the side and doesn't affect gameplay.

Except with games that have black borders, where it isn't present.

I will get some screenshots, however I don't have Pole Position to try.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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