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Steve Guidi

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Posts posted by Steve Guidi

  2. Posted

    On 1/17/2021 at 11:32 AM, Just Jeff said:

    Good Afternoon,

     

    I completed a composite mod on one of my 2600s and have some questions that I was hoping someone experienced with it could help me out with..  When it arrived the instructions were literally "watch one of the many videos online"  so I did that. I have not turned it on yet, mostly because I do not think it is correct. 

    The kit you have is a very common amplifier replacement that produces a composite video signal.  I built one using the schematic and installation instructions from the following page, which I'm fairly certain is practically identical to your circuit board.

     

    https://www.instructables.com/ATARI-2600-Video-Composite-mod/

     

    The difference between the kit and schematic is the omission of a resistor from video-out to ground, which darkens the output signal. You can review the instructions above including which components to remove and hopefully you can resolve any discrepancies with other YouTube videos.

     

    Also, I did not remove the RF modulator in my installation; no problems by keeping it in place.

    • Like 1

  3. Posted

    On 1/17/2021 at 2:07 PM, Reaperducer said:

     

    The big flaw with the manual's clock program is that it clears the screen first.  If you re-write it so that the clear command comes just before updating the text, it doesn't clicker so much.

    That's a great observation.  The structure of the program effectively has the screen cleared for a longer amount of time than when the text/time is on the screen.

     

    clear-compute-print-repeat v.s. compute-clear-print-repeat

     

     

  4. Posted

    On 1/1/2021 at 4:16 PM, Steve Guidi said:

    I really enjoyed putting the following video together, exploring what could be done with BASIC Programming.  I spent a whole day tinkering with the cartridge and was impressed with what was produced.

    Here is part 2 (of 2) of this series, where I explore the graphics, music, and keypad input features.  I also cover some memory optimization techniques that are needed while enhancing the clock program from the "BASIC Programming" manual.

     

     

    • Like 3

  6. Posted

    On 9/18/2020 at 7:20 AM, Steve Guidi said:

    I learned BASIC programming on the Commodore 8-bit computers, notably the C16 and C64.  I discovered this cartridge a few months ago and was completely bewildered -- the memory limitations, inability to save programs, the data entry; I had so many questions!

     

    So I recently bought the cartridge and built myself a pair of keyboard controllers just to play with it!  Looking forward to exploring this software!

    I really enjoyed putting the following video together, exploring what could be done with BASIC Programming.  I spent a whole day tinkering with the cartridge and was impressed with what was produced.  Yes, there are several limitations -- and they are frustrating if you have a background in computer programming, but somewhat manageable.

     

    The keyboard controllers are cumbersome, but you get accustomed to it within hours.  It helps that there is some logical organization of the symbols on the overlays.  It is also unfortunate on how precious of a resource memory is with this interpreter.  Just tracking variables costs memory -- you pay for every character rendered to the screen, visible or not!

     

    Lots of fun -- but only knowing full-well what you're getting yourself into when you try to write a "lengthy" program from the manual :)

     

     

     

    • Like 4

  7. Posted

    21 hours ago, -^CrossBow^- said:

    Pretty sure the text in basic programming is using flickering to simulate a more solid character and with a CRT the phosphor persistence would make it less noticeable. Many emulators too can make it appear to be more smooth than it is. So I think it is just the way your TV is interpreting the signal and flickering. What do the asteroid rocks look like as a comparison?

    Thank your for your feedback and confirming one of my thoughts about the cause: flickering and/or interlacing.  The asteroid rocks are clearly flickering through my upscaler and video capture card.

     

    WIN_20201128_10_03_23_Pro.thumb.jpg.f02f07717ef7673e351abf99ef995b05.jpg

     

    On my TV, the signal is not interpreted as cleanly -- sometimes the asteroids have jagged or incomplete edges, probably caused by some of the scan lines in the flickered signal being dropped.

  8. Posted

    Hi everyone!  I've been puzzled by the lack of clarity in the image that my composite-modded 2600 Jr produces.  I have a feeling that what I see is normal, but I can't rule out choosing a poor mod.  I've tried connecting my 2600 Jr. to my computer via an upscaler and a capture card, as well as directly to a LCD TV that supports composite video; both results are similar.

     

    To illustrate, below is a screenshot of "Basic Programming" produced by my NTSC 2600 Jr, and interpreted by my upscaler and video capture card.

     

    tIOW0DM.jpeg

     

    And the following is a similar screenshot which appears to be captured from an emulator.

     

    6a0120a85dcdae970b0120a86dde2c970b-pi.pn

     

    My image is a bit dark, and that can tweaked on the composite mod circuit by replacing a resistor.  However, I can't seem to produce solid text characters -- perhaps my TV and upscaler are interpreting an interlaced signal and the 16:9 upscaling is displaying the artifacts of that.  Is the text display in my image normal -- perhaps the emulator is intentionally producing a clearer image?

     

     

  9. Posted

    Master frikken Builder.  Probably easy to play today since we can take an instant and free photo of the screen.  You get a short amount of time to memorize the structure you have to build before the screen is cleared, for every level!

     

    I played this so much as a child that I eventually memorized the structure detail for the first level, then abandoned the game when realizing that this was just silly and impractical.

  11. Posted

    On 10/27/2020 at 4:59 AM, earthad1 said:

    My Atari 2600 Light Sixer Goes B&W When Tapped or slightly moved. 

     

    Any suggestions at what I should be looking at first?

    The color switch might be faulty, or the solder joints for the switch might have separated from the main board.  If you are comfortable with desoldering, you can test the switch after removing it from the board -- I'm not sure if it can be tested in-circuit. 

  12. Posted

    On 10/26/2020 at 5:46 AM, ianoid said:

    For example, I can turn it clockwise, and the paddle will register left to right, then once it comes back around there is a slight click, and then it jumps back to left and goes left to right again. Weird! 

    This is solely speculation, but it could be that the potentiometers are damaged so that their hard-stop has worn out.  When I last opened up a potentiometer, I noticed that I could get the wiper to spin continuously (and rejoining the track) if I didn't completely close the case/enclosure.

     

    Nevertheless, an interesting find!

    • Like 2

  14. Posted

    What is the maximum current that may be drawn from the joystick port (pin 7)?  I know that the +5V pin is typically used to power a small auto fire circuit in the joystick, but I'm wondering if it can power something like a compact Arduino or other microcontroller.

     

    The 2600 Jr. schematic by Jerzy Sobola shows "Vm" as the voltage source for pin 7 (and what appears to be the RF modulator), but I'm having trouble tracking the down where Vm is sourced from.

     

    https://atariage.com/2600/archives/schematics_pal/Schematic_2600_Junior_PAL.html

     

     

     

  16. Posted

    On 10/5/2020 at 6:39 PM, Jstick said:

    It does come with the original leather cover, which I don't see included in most other 2600 sales.

    Is that real Corinthian leather?  If so, that must be worth a lot!

     

    Also, there appears to be a switching power supply (replacement) with this unit.  Think of the energy savings compared to a vintage wall wart!

     

    • Haha 1

  17. Posted

    I've had a bunch of free time on my hands over the last several months: due to COVID-19 in the USA, all of my regular weekly activities have been cancelled.  In my search for new a hobby, I found my old Atari 2600 Jr. and modified it to emit a composite signal with the intention that my kids could play some of the neat games from the 1980s.  But I soon discovered some new problems: one of the two joysticks I own didn't move left, I sold my paddles long ago (with a Commodore computer) and my wife wanted to play "Breakout", and I also realized I never had the 12-button VTP/Kids/Keyboard controller to play "Star Raiders" and other games in my collection.

     

    What to do?  I could have bought the controllers on eBay, but there is no fun in that -- especially since they are straightforward devices!  So, I repaired and/or built them with some inexpensive components and project boxes.  I didn't even know that "Indy 500" and "Basic Programming" existed, so I bought the games just so I can build the controllers to experience them.

     

    I filmed the teardown/repair of the joystick and builds of the other controllers so that others can learn the same things I did (e.g. the keyboard matrix, rotary encoder, and deciphering Atari schematics) and have copied the links to the videos below for those interested.  I've included time-code indexes in the videos so that you can skip ahead to the build, wiring, or game-play (if you don't care for the technical explanations).

     

    I hope that this makes someone's future projects fun and easier to accomplish! :)

     

    (playlist)

     

    Atari 2600 Joystick: Teardown, Contact Mod, and Cable Replacement

     

     

     

    Building a Universal Atari 2600 12-button "Star Raiders" Controller

     

     

     

    Building Atari Paddles for Your Atari 2600 and Commodore Computers

     

     

     

    Building an Atari Driving Controller and playing Indy 500 on the Atari 2600

     

     

    • Like 4

  18. Posted

    6 hours ago, eizner23 said:

    I changed my mind. Didnt send it yet if anyone has anything else to add.

     

    atari-2k3.thumb.jpg.befda896b45a24c6562e13d2cc1431e9.jpg

    You should confirm if he's asking for Mexican Pesos.  At $2000 MXN, you'd spend about $92 US at the current exchange rate.

    • Haha 1

  19. Posted · Edited by Steve Guidi

    On 9/22/2020 at 8:18 AM, JayAre said:

    How about you guys?  Have you ever come across anything odd when opening a sealed 2600 game? 

    Not too odd, but I recently bought a sealed Polaris game from a USA eBay seller for about $5.  There was a sticker on the wrapping showing it was sold to the seller for $1 via a warehouse liquidation.

     

    I went to play the game and it didn't work.  I couldn't figure out why (tried on two flat screen TVs with composite and component input), but I kept telling myself that microchips shouldn't fail in storage under normal conditions.  On a hunch, I tried the cartridge on a computer monitor via an upscaler and the problem was now evident: this is a PAL cartridge and my TVs couldn't interpret the signal properly so they rendered nothing.

     

    Odd that someone had a stash of sealed PAL cartridges from a warehouse in the USA!

    • Like 1

  20. Posted

    On 9/11/2020 at 8:53 PM, ChuckTeed said:

    Just looking up tab repairs and stumbled upon this thread. How did the repair hold up? 

    I used some small screws to fabricate the broken tabs, then filed them down with a rotary tool.  I don't think I'll have any issues with this in the long term.

     

    See the following for photos (I misinterpreted what the OP was asking in that post).

     

     

     

  21. Posted

    I learned BASIC programming on the Commodore 8-bit computers, notably the C16 and C64.  I discovered this cartridge a few months ago and was completely bewildered -- the memory limitations, inability to save programs, the data entry; I had so many questions!

     

    So I recently bought the cartridge and built myself a pair of keyboard controllers just to play with it!  Looking forward to exploring this software!

    • Like 2

  23. Posted

    Hello!  I'm wondering of anyone has investigated the feasibility of modding a 2600 so that you can switch between clock frequencies and/or color palettes.  The goal of such a project would be to play cartridges of differing regions on the same machine.

     

    I've seen a similar project on a Commodore 16 where the clock crystal was replaced with an Arduino, the latter programmed to output different selectable frequencies to produce a signal for PAL and NTSC video.

     

    As for the color palette, I believe that would require a swap of the TIA chip, which could be done manually if the board is socketed.

     

    I haven't studied the schematic, and a cursory search doesn't show anything useful.  To anyone with the hardware experience, do these ideas seem sound?

     

    My assumption is that the only difference between a PAL, NTSC, and SECAM 2600 are the clock crystal and TIA since the game cartridge does all the video synch.

     

    Steve Guidi

  24. Posted · Edited by Steve Guidi

    Edit -- I read this message again and I realize that OP is likely talking about the pins inside the cartridge connector, not the "pins" that open the dust cover on a cartridge.  Sorry for the distraction!

     

    ---

     

    I understand that this is a very common issue with the 2600 Jr.  My childhood 2600 Jr. developed this same problem when I first got it, but I was able to patch it recently with some small screws and washers.  I used a rotary tool to flatten the top of some wood screws, then threaded them into the spots adjacent to where the broken pins are.  You can probably use machine screws too, which don't have a point.  I believe I used a #4 screw (North American size); pick one that requires minimal threading to clear the slot -- otherwise you risk breaking more plastic!

     

    IMG_20200808_203812.thumb.jpg.f9d724efed56646c6225f0dede148858.jpg

     

    Don't worry -- there is ample clearance between the cartridge circuit board and the screws and nothing will get damaged.  The washers are optional, but help secure the screw in the cartridge slot.  You can use some glue to further strengthen the placement of the screws if desired.

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