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Thread: My Atari 2800 Mod project "Wireless Woody"

  1. #11
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    I don't think that the cap is really needed, the Atari is very tolerant as it had a dirty power supply, and your feeding clean DC from the batt. Also, there is a 5 volt reg on the Atari board, I can't recall the input range, or if there is anything ahead of it to worry about, but a 9v reg may not even be needed.
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  2. #12
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    Scott, are you aware of the Composite video mod for the 2600? I've been looking on sites and it looks simple, but there's one slight problem. The Motherboards I've seen on sites appear to be on one board. I opened mine up, and it's on two boards...



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    Maybe these numbers mean something to you Scott...?



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  3. #13
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    Quote Originally Posted by SubaruBrat View Post
    I don't think that the cap is really needed, the Atari is very tolerant as it had a dirty power supply, and your feeding clean DC from the batt. Also, there is a 5 volt reg on the Atari board, I can't recall the input range, or if there is anything ahead of it to worry about, but a 9v reg may not even be needed.
    Oh really now? Does that mean I can run the Atari on a lower voltage then? That's interesting, still I might end up building that power distributor board of the hell of learning how to build a regulator, lol.

  4. #14
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    Quote Originally Posted by SubaruBrat View Post
    11.1v should be close enough. The battery I put the link to is equall to a 2.2AH lead acid, and is about 1/5 the size and weight.

    Battery: http://cgi.ebay.com/11-1v-2200mAh-3S...item2eb664719d


    Charger: http://cgi.ebay.com/Venom-2-3-Cell-L...item35b3f77d0d


    I was also thinking, you could install a Harmony multi-cart mounted at 90deg and you would not have to worry about cart access as all the games would always be on the unit.
    Speaking of these batteries, I can see the Positive and negative cables, but what on earth do the other cables do?

  5. #15
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    Quote Originally Posted by SepticLemon View Post
    Ah... ok, a rechargeable battery for an RC car, interesting... There's a brand new model shop near me, I might see what RC car batteries they have, and hope they got something close to 12V.

    Oh and just an update, I received my 2600 today, been playing Demon Attack and Yar's Revenge on it. One slight problem, the joystick's up direction doesn't work, I'm going to email the person who sold it to me and find out if I can get a replacement or a refund.
    If a refund doesn't pan out, open up the joystick and look at the board. The directional switches are just little "pimple" things under a tape-like film. They're known to kind of slide around over time and move off their contacts. If it looks like that might have happened, take a razor blade, cut the up-direction switch out, center it properly on the contact, and stick a piece of scotch tape over it to hold it in place.

    If the pimple thingy is cracked, this won't help you.

    Also, the problem might be the actuator (tab on the white plastic stick that actually operates the directional switches). Those CX-40 sticks are a bit brittle, so if there is a crack in the ring that provides rigidity to the actuators then you're probably not getting enough force to close the switch.
    Check out CYN CITY:
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  6. #16
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    I did the video mod on mine and it was a heavy sixer, yours is a later production board but the mod would still work.

    Oh really now? Does that mean I can run the Atari on a lower voltage then? That's interesting, still I might end up building that power distributor board of the hell of learning how to build a regulator, lol.
    Look up the specs on the regulator, it will specify the input voltage range, it will be more than 5v so in theory you could get down to maybe 7 or so, search for the part # and see.

    Lipo batteries can be charged by the main leads, but the cells can charge at different rates and end up unbalanced. The other cables are individual cell connections so that the charger can balance the cells individually.
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  7. #17
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    Ok, I've been looking at this page for the Video mod...

    http://forums.benheck.com/viewtopic.php?t=1151

    I've located the spot for audio, which is capacitor C210. However I can't seem to figure out where the chroma is, that page points to what looks like another cap, but it's different on my board, it's lined up with a bunch of other resistors. There's a cap labelled "C212" and "C213". Which one of these is the chroma cap?

    Secondly it mentions the pins on the under belly of the board that's attached to the Stella Chip, thing is on his photo his Stella Chip is really low on that motherboard. The first chip on my board is about 2 or inches from the bottom of the board, and it's labelled "8046 C011903-03". Thing is I remember the number "8046", isn't that a logic gate? I swore I sold something like that to a customer I had at work, maybe I'm an idiot and should know more about my ICs, lol.

  8. #18
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    Ah ha! by the power of research I found this!

    http://amazingdiy.wordpress.com/2011...600-video-mod/

    Being a Brit, I use PAL, and arrantly there's two versions of the Stella Chip, one for NTSC, and one for PAL. However it has a different pin out!



    going back to the Ben Heck forum page, if I was to work on the NTSC Stella chip I need to work on pins 2, 5, 7 and 8, which are the c-sync, Lum0, Lum1, and Lum2 pins. Looking at the picture above, C-sync is still on pin 2 on the PAL chip, but Lum0 is now on pin 7, Lum1 is on pin 5, and Lum2 is on pin 6. Therefore, pin 7 and 8 on the Ben Heck page becomes pin 6 and 7 for the PAL chip.



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  9. #19
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    Ok, more research!

    WINNING...

    I've been studying the motherboard, the pins on the Stella PAL Chip, and where things go. What I discovered is that pins 2, 5, 6 and 7 all go to a selection of resistors, but these resistors are all 3.3K Ohm. The diagram above with the Pots and 22 ohm resistor might be there just for NTSC output. So I thought rather then use pots and another resistor, I'll wire up these contacts...



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    AMENDMENT: the first resistor on the left is for the C-Sync.

    Here I've pointed out where the Luma, Chroma, and Audio are on my board, technically I should be able to wire up the Luma, Chroma and C-Sync together to make my Composite video out. The only thing that bugs me is the resistance/impedance, why are my resistors different to the ones Ben Heck diagram, is it because of the PAL signal? Should I stick to the resistors on the board? Or should I use something different?

  10. #20
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    Ok here's my composite video mod design...



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