Jump to content

Steve Guidi

New Members
  • Content Count

  • Joined

  • Last visited

Everything posted by Steve Guidi

  1. SpectraVideo's keyboard product came with a Microsoft Basic implementation that had much more RAM, but it also included other limitations like only being able to edit a line once during program entry.
  2. The paddles are built with a 1M-Ohm potentiometer, which is given 5V from pin 7 in the controller. The system detects the "resistance" by measuring the time taken to charge an internal capacitor. If the capacitor is out of spec, then the charge time will vary and produce a different and incorrect reading of the controller's potentiometer. I suspect this is the case since you've verified the correct behavior on the other joystick port, using the same controller. Here's a link to the schematics showing a .068uF capacitor used on the analog input pins (5,9 for paddle inputs). Perhaps you can just replace the ones used on the misbehaving port. https://www.atariage.com/2600/archives/schematics/Schematic_2600_Low.html
  3. Not ideal, but you can use a battery pack to run the Atari 2600. You need about 7V to overcome the voltage drop off the regulator and get 5V on the output. I've used 6x1.2V NiMh cells with about 2000mAh. That will last about 4h for a 500mAh draw, which is what the original supply is rated for (Atari 2600 Jr., NTSC).
  4. To be honest, I don't remember. I haven't played this one seriously in about 30 years 🙂
  5. There are some games that requires this, but I don't recall if Raiders is one of them. As for the game play, one of the first rooms you will enter will become sealed and inaccessible after some time had passed.
  6. This guy claims to be selling the complete Zellers collection, but unfortunately your cartridge is not shown. https://www.ebay.com/itm/Atari-2600-ZELLERS-The-Complete-Collection-Video-Game-Console-System-Lot-/293563824995
  7. 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.
  8. 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
  9. 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.
  10. 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
  11. 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. 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.
  12. 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. And the following is a similar screenshot which appears to be captured from an emulator. 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?
  13. 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.
  14. This one definitely requires the manual. The hint section is basically a walkthrough.
  15. 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.
  16. 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!
  17. Awesome! Thank you for confirming. I looked up the technical specs on the Arduino Nano and it draws 19mA of current. That should be well within spec of the 2600.
  18. 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
  19. I was really surprised to see the ice-sliding and friction-deceleration dynamics in Indy 500 -- the game is from 1978!
  20. 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!
  21. 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
  22. You should confirm if he's asking for Mexican Pesos. At $2000 MXN, you'd spend about $92 US at the current exchange rate.
  23. 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!
  24. 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).
  • Create New...