tetrode kink

Did bubble-wrap even exist in 1980? -tet

OMG, I loved the old DAK & JS&A catalogs. I loved the long descriptions, something you just didn't see very often elsewhere. I bought a few things from DAK, including my first CD player (for my stereo system, not a portable), and my first PC-compatible computer. The computer was a 486. It was originally 25MHz and had 4 MB of RAM and a 120 MB hard drive. During its use I bought the 75MHz Overdrive for it, upped the HD a few times, and had to take out a loan from one of those consumer loan companies for $400 to buy 16 MB of RAM!!! I still have it in the basement, though I haven't fired it up in years. I know I still have a few of those old DAK catalogs around here somewhere. I can't believe they're worth anything, though. It's kinda cool that DAK/JS&A were in some way connected to an obscure piece of Atari hardware, whether or not it actually made it to market. -tet

As others have stated, your paddles are working correctly. I think the reason it works this way is because back in 1977 it would have been too expensive to include analog-to-digital converters in the VCS circuit design. Nowadays, AtoD conversion is a dime-a-dozen, and it would read the paddle position in the background. The hardware would just assign a number from 0-255 to the current paddle knob position. All the programmer would have to do is read the number whenever he wants to see where the knob is, then position the character accordingly. On the VCS it's a completely different story. The programmer actually has to write code to charge a capacitor, wait a bit, then read the register that represents the capacitor's state to see if it has discharged yet. This waiting-and-reading sequence has to be repeated dozens or hundreds of times in game code just to get one read of the paddle's position. The time it takes to discharge the capacitor determines where the paddle knob is positioned. The thing is, it takes an achingly long time to discharge the cap, about two full video frames' worth. This amounts to 1/30 of a second, which doesn't sound like much, but in game code 1/30-second might as well be forever. If the programmer can afford the code-execution time to completely discharge the cap, the game will make use of the whole paddle. Unfortunately, reality makes this almost never possible. Considering the program spends about 3/4 of its time just keeping the screen alive, it's not surprising that most (all?) paddle games only devote enough cap-watching time to make use of part of the paddle's range. Also, perhaps because the VCS's paddle-handling hardware is so primitive, programmers came up with different code schemes for reading the paddle. This is why different games use different areas/ranges of the paddle for game input. Interestingly, there has been talk here of workarounds to this limitation. This thread, started by tremoloman2006, asked if there was a way to make a paddle less sensitive so that it used more (or all) of its range. That spurred quite a response, in which several ideas were discussed. So far there is no solution which would use a paddle's range for all games. But there were several ideas (including schematics) for a down-and-dirty solution involving modding the paddle with a few parts so that it doubled the paddle range for any game, with a switch included so that the paddle could be switched to "original" mode when desired. HTH, -tet

Just FYI, the disc spinning at different speeds is normal behavior. It's called CLV, or Constant Linear Velocity; where the pits and lands on the disc are the same size and distance apart at the outer part and the inner part of the disc. Thus the disc slows down as the laser travels further out to the edge, so that the bits flying by the laser appear at a constant frequency. Contrast this with CAV, or Constant Angular Velocity, which is how phonograph records and hard drive platters work. These discs rotate at the same speed at all times, so the information at the outside of the disc is actually wider and farther between. The CLV method is a more efficient way to store information, allowing optical media to store more than if it used CAV; CAV wastes a lot of otherwise usable space toward the outer edge of the disc, what with all the wider spacing of information. -tet

Just a heads-up, Dave S. Because the paddle handling hardware on the VCS is extremely primitive - and game programmers had differing ways of coding a paddle read - some Atari 2600 paddle games use different areas and ranges of the paddle pot. Thus while your partial-range paddle mockup works on one game, it may not work on all of them. Of course, you're just experimenting now, so that it works at all is amazing! But in the end product, I urge you to strive for one full megohm paddle range to guarantee that the controller will work for all games. [edit] Oops, forgot that the variation in paddle area/range isn't limited to coding variety. Though the effect probably isn't as great, parts tolerances - such as in the caps that are used to time discharge (thus paddle pot position) - can cause variation in pot area/range in different VCSs playing the same game. [/edit] -tet

I noticed this once as well. It was a post here at AA where someone posted pics of what was obviously a light-sixer because of the thin plastic on the sides. But the black plastic across the bottom of the woody panel had just an ever-so-slight curve to it. At the time, I convinced myself I was either hallucinating or it was an image defect. When taking very close-up pics, cameras introduces distortion to images where straight lines appear curved. Some cameras handle this distortion better than others. -tet

See, Pioneer, toldja it was a great idea! FRY IT! Couple thoughts: There's only one thing I can think of (so far) that might make a "FRY IT!" button a bad idea. It's mentioned in batari's post about the Video Game Brain: Not being a chip expert, I wonder if there are is any danger to the RIOT if it is de-powered while voltage is present on its signal lines. On the fun side, there's no reason you couldn't press the "FRY IT!" button multiple times in a game: One "FRY IT!" didn't frazzle the game enough for you? "FRY IT!" again! Fry well, my droogies, fry well. -tet

Good (great, actually) idea P4x4, but if you reset the CPU it's practically the same as powering off-then-on. [edit] Normal power-on, I mean, not frying... [/edit] Either way, the CPU goes back to its default starting point in the program, which means RAM gets zeroed-out and then set up for a proper game. What fun is that? :o What am I saying!! Of course Atari games are fun... You know what I mean... Forget I said that... I think what you'd really need is a cutoff to momentarily remove power from the RIOT chip, which contains the RAM. Like maybe cutting the power lead or a circuit trace leading to it, etc., and inserting a normally-closed, momentary pushbutton in the circuit. A quick push of the button would temporarily power down the RIOT while the rest of the console was still running. When the RIOT comes back up, presto-change-o, scrambled memory, scrambled game!!! Talk about controlled chaos! Then the fun really begins! -tet

+1 for you, Rex! If you want to read a dumb rant on the subject, check the link in my post, a few posts up from here. -tet

Umm, someone more experienced correct me if I'm wrong, but don't all Six-Switch Ataris have the heavier shielding? I thought they only started using the lighter shield in the single-board, 4-Switch models. Furthermore, I was under the impression that the reason for the weight difference between a Heavy-6 and a Light-6 isn't the shielding, it's the plastic. The Heavy-6 had a ton more plastic in its bottom casing than the Light-6. Again, I've personally seen the insides of precious few Ataris, so I invite correction from more experienced Atari fixers, etc. -tet [edit] Strategically added the word 'for' in the appropriate spot... [/edit]

Ah, thanks for the clarification. Just goes to show, capitalizing acronyms makes a world of difference! As for the all-important info your readers all want to know, um, well, it's chronological... -tet

From reading your post, I know you meant "derivative" in the best possible sense. I would just watch how I use the word "derivative." Of course you mean Arkanoid derives its basic premise from Breakout, but adds all sorts of fun power-ups, random hazards, etc. But sometimes the word "derivative" can have a negative connotation. I believe this is because many times people have used the word "derivative" when they either meant "dilute," when the follower was somehow less exciting or fun than the original, or "one-dimensional," when the follower used only one element of the original. Yes, in a pure technical sense, Arkanoid was derivative. But it was the exact opposite of the latter two adjectives: It didn't dilute Breakout, it enriched it. It didn't subtract dimensions, it added them. I know that's what you meant when you said, "derivative." Because I already liked Breakout, Arkanoid totally blew me away when it came out. One of my favorite coin-ops ever. -tet

Aww, really, dude? Playing your Atari on a widescreen? Really??! Man, if you must do that, at least get into the menus and tell your TV to stop stretching NTSC signals to 16 x 9. Atari should be played at 4 x 3, as Lord Bushnell intended. -tet

Also, I don't think the "sellotape" (did you mean 'cello tape,' as in cellophane tape?) is an issue. If everything's as it should be, the tape residue is just on the board around the dome switches, where the tape holds the domes over the contacts. Now, if there is residue on the contacts themselves (under the domes), by all means clean it off. It could very well be what's preventing the left direction from working. -tet

No, if you open up a DC you'll only see 4 wires, ground, up, down & fire. Wow, thanks for clarifying that, Buzbard. OMG, that little tidbit makes it stupid-easy: With no further modifications, your cool little joystick tester is also a Driving Controller tester! -tet

First of all, nice find, Gigabyte! Next, what is this 'gaming Ian center' you speak of? Is it a place for gaming owned by Ian? Is it a gaming place owned by anyone but you'll always find a guy named Ian playing there? Was AtariAge Forum member @ianoid there? I've dealt with him on eBay, and he's a super guy. I wouldn't be surprised if he was fun to game with, too. Finally, you left out one very important detail about your system. I'm sure all us readers would love to know. -tet

Well, I probably shouldn't answer this, since doing so could contribute to the possible ruination of someone's console. But, apparently, I just can't help myself... Starting with the power switch in the "on" position, quickly flip the switch off and then back on as fast as you can. Usually you can't turn the switch off and on fast enough for that technique to work. So what you have to do is maneuver the switch into an "in-between" position, where it rests at power-on but if you tap it with your finger it goes off for a tiny instant. The momentary power-off event must happen fast enough so that the VCS's internal electronics don't force the CPU to reset, thus the CPU continues executing instructions where it left off before power loss. This means it doesn't get to execute the memory zero-out routine normally found at the beginning of most game programs. Since the console's RAM contains random information at power-up, preventing the CPU from zeroing it out (and presetting it with normal game parameters) results in various kooky, unintended game behavior. There, I said it. I leave it to the VCS owner to assume responsibility for any damage, however slight the chance it happens. Yes, there is a risk of damage, which is why all video game manuals warn against it. As someone mentioned previously, excessive power cycling could potentially send the console to an early grave. Any time you turn it on, the console takes a very small "wear & tear" hit; both the power switch (mechanically) and the circuit board (electrically). If your particular console contains a part or parts which will someday fail because of power cycling, frying will bring that day sooner. Understand, the chance is very small, but it exists. In the end, it rests on whether or not the console's owner is a gambler. One should never pull a cart while power is on. The chance of frying (to death) the cart is much greater doing this than with power-switch "frying." Fortunately there is no advantage to be gained by pulling an Atari cart, because the game program itself has constant, direct control of the video; so when you pull the cart the screen will either display garbage or go black. -tet

Cool story! As to how I learned how pulse dialing worked, I can neither confirm nor deny from where I didn't not learn about it, nor whether it wasn't not from the phone phreaking craze that was or was not happening at the time... OK, I can confirm that I indeed did not learn it from phone phreaking, as in Woz calling the Vatican for free with his little blue box, etc. I'm pretty sure I read it somewhere; I think it was when I read about Strowger switches. We didn't have an encyclopedia in the house, and of course there was no Discovery Channel at the time, so I must have read it in a book from the public library. BTW, I wish I had known about phreaking, since it was happening at exactly the time I was a benignly-mischievous, "how stuff works"-hungry teenager. I just wasn't plugged in to the right info streams, I guess. -tet

Well, since no one's mentioned it, there's the age-old fry trick of Space Invaders allowing you to have two active shots on-screen at the same time, rather than the normal one. But then later we all learned that that exploit was available in the game by just holding down the reset button while you turned the power on. We all learned that, right? None of us are still frying our Space Invaders, prematurely wearing out our power switches for that exploit, right? I can understand the appeal, especially to a kid. Kids are always excited to experiment and discover new things, new ways to play, etc. But I just don't do it today (nor at all since I "rediscovered" my Atari). As I get older I don't want to put my VCS(s) through any more wear and tear than necessary. Just playing the games normally is fun enough for me. -tet

What, you have something against paddle games, Mister?! The info is widely available. Paddles are simple. It's just a one-megohm pot plus the fire button, two of each per connector. If you went the mechanical meter route, all you'd need is a resistor and a switch (so you could test both paddles). When testing, if you watched closely you should be able to see the meter needle twitch for a badly-jittering paddle. But a single, very tiny bad spot in a pot might be too subtle to register on the meter, yet would still be unusable as a paddle. The Driving Controllers are just another kind of switch. IIRC, it's four metal "finger" switches on a disc which is turned by the knob. The disc has a metallic pattern on it which contacts different finger combinations as you turn it. The pattern makes sense to the game program, but for testing it wouldn't really matter which switch goes to which LED; as long as all four LEDs light as you turn the knob, it's good. Well, that really should conclude my pontificating on a wanna-have tester. I've spouted way too much already considering I have no intentions of building one myself. -tet

You could say Bigfoot was a huge pickup. I also kinda liked Scarlet Bandit and Grave Digger. -tet

Wow, that's great! Totally cool that you put it in a cart! But it seems incomplete. It also should be a Paddle Controller tester and a Driving Controller tester. The DC tester wouldn't be too hard. It's been a while since I've seen a DC schematic, and I've only seen the inside of one in pictures, but IIRC the rotary control uses the same four direction lines as the joystick; as long as it lights up all four LEDs as you turn it, the contact "fingers" in the control are good. If the DC uses different lines, it's just a matter of rerouting lines to the LEDs with a switch. The Paddle tester would be harder. The easy way would be to just hook up an analog meter movement to it, but I'm afraid mechanical meters aren't quick enough to transduce paddle jitter. You could hook up an LED meter bar so that jitter would be easy to spot, since LEDs respond practically instantly. That would be a more complex circuit, though, and now your controller tester cart is getting pretty crowded inside! Still, as-is, that tester is really sweet! -tet

*Ahem* With all due respect to Mr. Mercedes Man, there is only one CPU in the Atari. The TIA is a special-purpose interface, sound & video generating chip, not a CPU. With that out of the way, among other things, JacobZu7zu7's VCS problems could very well be caused by a bad TIA, especially the Sears. It sounds like collision detection is intermittent/failed. -tet

If one could date an Atari 2600 system, I'd never leave the house. -tet

Eh, that's not Ren. That's some bastard's version of the Taco Bell Chihuahua. Since you're obviously not a "Ren & Stimpy" fan, I'll forgive you that insult to Ren. Once. -tet