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rednakes1

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Posts posted by rednakes1

  2. Posted · Edited by rednakes1

    Use a DPDT switch for Pause with No Sound. Connect Ground and Pin 50 ('wait' on the expansion slot) on one side for Pause function. Connect Audio Source (C88 cap on back of board) and Audio Output (on RF module or A/V mod) to eliminate continuous sound.

     

    Here's a link to a pic I helped a friend with: http://atariage.com/forums/gallery/image/10335-colecovision-pause-mod-example/

    This is one of the more useful mods out there. I finally got the courage to try this out after doing the A/V mod months ago. Thank you very much for the diagram. The only hard part about this hack is drilling and filing the rectangular hole to put the switch in. It took me an hour to file it (after drilling two holes) but that's because I was being very careful.

     

    You can also mount the switch at the back like I did so that it doesn't "ruin" the original look of the console. See my attachment.

    post-47549-0-40015900-1498199972_thumb.jpg

  4. Posted · Edited by rednakes1

    Just wondering anyone has any idea about this problem concerning a rolling interference pattern on my AV-modded Colecovision.

     

    I'm attaching a photo to demonstrate what I am seeing on my CRT TV. It's a set of diagonal rolling lines on the screen that disappear after several seconds and then show up again. It drives me nuts, especially in games with a blue background (eg. The Coleco blue skill selection screen, or Evolution title screen).

     

    This problem is most visible on my AV (composite) connection but also shows up on the RF coax input as well, though not as noticeable because the lower quality hides it a bit. I've tried the transistor AV mod as well as the op amp version of the mod, and neither rectified the issue.

     

    I've also tried two different power supplies, cleaned the power switch and PCB, and tried different TV sets (CRT and LCD). I don't want to waste any more time on this but was just hoping someone can help out.

     

    Someone else had this same problem a couple years back and he ended up selling the unit and buying another one, which didn't have the problem. So it wasn't an issue with his power socket or location.

    post-47549-0-78889100-1496933342_thumb.jpg

  5. Posted

    Bumping this old thread because I have been pulling my hair out trying to fix the same issue. Jeremy mentioned he eventually sold this CV and got another one later that worked better. So it doesn't look like an issue with his location and power socket.

     

    I'm attaching a photo to demonstrate what I am seeing. It's a set of random lines on the screen that show up, disappear after several seconds and then show up again in the same or different orientation. It drives me nuts, especially in games with a blue background (eg. The skill select screen, or Evolution title screen).

     

    This problem is most visible on my AV (composite) connection but also shows up on the RF coax input as well, though not as noticeable because the lower quality hides it a bit. I've tried the transistor AV mod as well as the op amp version of the mod, and neither rectified the issue.

     

    I've also tried two different power supplies, cleaned the power switch and PCB, and tried different TV sets (CRT and LCD). I don't want to waste any more time on this but was just hoping someone can help out.

     

    Mine is a Revision J motherboard.

    post-47549-0-17336800-1496894558_thumb.jpg

  8. Posted · Edited by rednakes1

    Okay, figured it out! Pin 8 on the controller port (which controls the joystick and left fire button) goes to the grey connector at the bottom of the PCB. With my multimeter I noticed there was no connectivity between the grey connector and the track that leads to a solder point near the middle of the controller, which was likely due to a broken trace again. So I soldered another wire...and now it works!

     

    Here's a photo attached. Pardon my shoddy solder job, but it works now and I'm happy ;)

    post-47549-0-03319600-1496698274_thumb.jpg

    • Like 1

  10. Posted · Edited by rednakes1

    Yesterday I tried out a Colecovision controller that I bought at the flea market for very cheap. Unfortunately, I got what I paid for, as it has been giving me a lot of grief.


    The original problem was that the Up and Right directions did not register at all. With my multimeter I was able to narrow this down to damaged traces on the PCB. So I fixed this problem by connecting a wire to the parts that could not be reached by the Up and Right direction contacts, as can be seen in the attached photo. Afterwards everything worked great, the controls were smooth and perfect!


    However, after a few minutes I noticed that the controls intermittently would stop working for a second or two, and then come back again, and then stop working again. This went on for a few minutes and got worse and worse (longer stoppages), until none of the controls except for the Right fire button worked at all. I noticed all of the keys on the keypad were working as well.


    Does anyone know what could have caused this?? Judging by the intermittent behaviour, it seems like a cold solder joint somewhere but I don't know how to narrow it down. Do all the controller directions and left fire button eventually share a common point? I can't figure out why only the right fire button is working (along with the keypad). Could this be a diode issue?


    I also tried my other Colecovision controllers on the same controller port and they work fine.

    post-47549-0-49524200-1496643352_thumb.jpg

  11. Posted · Edited by rednakes1

    This is the picture I took last year, so here are the connections. (See attached)

     

    The wires are really thin in this kit so I wonder if that has any impact.

    I did put the RF shield cover back on and routed the wires out a hole, but that makes no difference.

     

    EDIT: From top to bottom, the wiring is: Ground, Audio, Video, 12V

    post-47549-0-19350300-1495109567_thumb.jpg

  12. Posted

    I did a composite mod last year in my CV using the kit from coolretroprojects. Unfortunately the kit actually made it look worse so I went back to my coax connection. Now that I have some time I would like to investigate this further. Also I could also attempt a different mod using my own parts.

     

    For instance, I see a fair bit of noise in the screen with the composite output... kind of like faint diagonal lines one moment, then horizontal lines, then other types of interference patterns. It's not horrible but the changing noise gets annoying on games with blue backgrounds such as the Evolution title screen.

     

    Anyone else had this experience? Ideas?

  13. Posted

    Not as good video output. And some units exhibit faint jailbars. But at least the colors can be enhanced by performing the 820ohm resistor mod across a couple of pins on the TIA chip.

    This resistor mod is only for the Rev 14 and lower motherboards for the 4-switch woodgrain atari 2600s. Not the Jr, which has superior colour to the 4-switch. I haven't been able to compare to a 6-switcher however.

    • Like 1

  16. Posted

    So we can reasonably conclude that there are 6-switchers, 4-switchers and Jr.'s that have jailbars and those that don't.

     

    The problem is either: (a) there were some Ataris that were 'faulty' to begin with, or (b) there are components that degraded over the past 30+ years. Or all of the above ;)

     

    I do take this as a challenge to figure out why my 4-switch is showing jailbars, so maybe sometime in the future I'll look into it at more detail. Any recommendation for a reliable but inexpensive oscilloscope would be great.. I've noticed there are now USB oscilloscopes and mobile-based (iOS/Android) ones as well. It's been a while since I've used one.

     

    In the meantime I'll just enjoy the Xmas break ;-)

  20. Posted

    If you operate in the digital domain entirely you'll never have to deal with interference or image inconsistencies. You can tune emulator Stella to soften the image a little and add very subtle scanlines and artifacting for texture.

     

    When I was a kid I could only dream about having such image quality.

     

    And I think that the digital mod is the only way you're going to be satisfied if you're sticking with real hardware..Amiright?

     

     

    I originally had the Flashback 2, and going from that to the 2600 was awesome, but the bummer was seeing the jailbars. So it's been annoying me quite a bit LOL. I have various Atari emulation devices already (RetroPie, PC, Mac, PSP, PS Vita), but I enjoy playing on the actual console instead.

     

    I think the FPGA mod would just be the easy (and costly) way out. And who knows, maybe there will still be jailbars! There's gotta be a simpler solution. For me, it would also be nice for us to find the fix/workaround so that it could help others as well. I've learned a lot from doing this.

  21. Posted · Edited by rednakes1

    Don't forget that RF interference and composite noise is part of good old days goodness. If you are looking for perfect clean RGB arcade picture (not Atari 2600 anymore)... just go for Stella and some sort of VGA to RGB interface... or just plug anything into HDMI port of a LCD and you have ... the disaster... Come on man, just be reasonable!

    But that's why we are here ;) to get the most out of our aging devices and keep them maintained well into the 21st century.

  22. Posted

    Crap, bad snowstorm today. Doubt I'll get out to the game store today. I'm never going to get this system checked.

    Have you tried checking for jailbars without a cartridge inserted, when it shows those random patterns? I still get jailbars when it shows the colours... if it's a bright background then I can easily see them.

  23. Posted

    im not saying to give up by the way, but your not going to fix it by stabbing random crap, I have spent a considerable amount of time debugging it with tektronics and HP high speed meters, logic analyzers and oscilloscopes, and the only time I can actually get rid of it is if I blur the picture to absolute crap on a LCD TV, its just a fact of life on these older machines

     

    heck here is a pure digital CGA to ntsc example I made and its got horizontal jailbars in the signal from who knows what cause it doesnt show up on the TTL digital monitor I have, maybe its the CFL lightbulb 8 foot above

     

    When I was working on my AV mod, I had tried different schematics. In one of them I observed that if I put a cap at a certain spot of my circuit it would make the vertical lines fade out a bit, but in fact it was merely blurring the pic.

     

    Right now I realize if I turn down the sharpness all the way on my CRT - in effect, softening the picture - the jailbars are diminished a tiny bit. Especially on Aquaventure... that game looks like crap with jailbars.

     

    Anyways I think I am ready to give up. If you want to take a look at my motherboard perhaps I can send it in during my xmas vacation. I'm in Canada though.

     

     

    BTW in the attachment, does my 2200uF cap look okay? The black end looks a bit cruddy. I just want to be sure everything's alright and not impacting the picture.

    post-47549-0-99515400-1481350492_thumb.jpg

  24. Posted

    Taking a break from brainbeating interference issues..

     

    I'm not sure which of the "modern-tech" enhancements is most valuable and does the most to enhance the classic gaming experience:

     

    1- This style of programmable video mod, that digitally recreates the image with exact timing.

    2- Flash carts and their interfaces to modern memory technology.

    3- Modern development tools, emulators, and debuggers.

    On a related note, I probably would've stuck with a cartridge modded Flashback 2 if it was compatible with all the games. It had a near perfect picture - slightly dulled colors but no vertical lines or blurring. I wish they could do that again. I see someone else made the Walkman-style Atari on these boards so I hope there's more to come.

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