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Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment. |
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1st Oct 2017, 1:44 pm | #21 |
Rest in Peace
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Re: Old arcade games
It's unbelievable Chris, when you think that nowadays even the simplest software seems to need acres of memory. The graphics were still pretty good if I remember right. Some of the tubes looked like the pixels were almost oblong, but maybe this was down to the tube rather than the software? I remember many a happy night playing Galaxians and Space Firebird. The sound effects are still clear in my head.
Alan. |
1st Oct 2017, 3:13 pm | #22 | |
Dekatron
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Re: Old arcade games
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1st Oct 2017, 3:22 pm | #23 |
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Re: Old arcade games
It was the eighties, and I was but a teenager, and for the time it was cutting edge. You are right, nobody would accept those graphics nowadays, what with 3D UHD and the like. But it was of the time. Rose tinted spectacles and all that. Things don't seem half as exciting nowadays...
Alan. |
2nd Oct 2017, 3:43 am | #24 |
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Re: Old arcade games
In my view, many of the coded versions of the original arcade games like Pong, Tank, Asteroids are very poor facsimiles of the real thing. Its better to get the real arcade boards/games if you can.
Even going back to the simplest examples, the reason coded (PC) based versions of the original ARCADE Pong were poor compared to the originals was because the coders had no knowledge of the original Pong circuit architecture in terms of the way it operated and made the game play. For example in Pong, it turned out after the circuit analysis was done there were 42 states of motion of the ball and the specific paddle and ball interactions were elucidated. The reason this wasn't common knowledge prior to the year 2012 publication cited below was that Atari didn't publish a "functional analysis" only the schematic....and it was not self evident from looking at the schematic what was happening. The circuit analysis was in fact "missing". This left the coders in the dark, so what they made looked like a pong with the ball bouncing off paddles and the screen edges, but it played quite differently. (just like coded versions of other classic arcade games) I wrote a very detailed description of Pong's circuit architecture which revealed the details, including the 42 states of motion, but even then, as explained in the article there was a PCB defect in the original Syzygy pcb's that reduced these (now called the Ghost in the machine bug) there were actually 6 bugs, also it contains interesting remarks from an interview with the inventor, it is here: http://worldphaco.com/uploads/LAWN_TENNIS.pdf Still, I have yet to come across a computer version that plays anywhere near as well or similar to the original Arcade version. The closest would be one implemented with an FPGA by a fellow in Germany. The same applies to Tank & Asteroids, but of course many people not particularly familiar with the subtleties of the original Arcade games would be perfectly happy with the coded versions. Also people were generally happy with the home Pong game, but many compromises were made when they forced the 66 TTL IC's of the original arcade pong into one LSI IC. Another related article is here on a miniaturized version of the arcade pcb which discusses the bugs in more detail: http://worldphaco.com/uploads/ARCADE_MINI-PONG.pdf |
2nd Oct 2017, 11:21 am | #25 | |
Nonode
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Re: Old arcade games
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One of the things I find fascinating about the design of these games is the amount of electronics devoted to creating the video display. There are typically anything between 50 and 200 or more TTL logic ICs, most of which spend their time doing something to do with the graphics. The whole thing is optimised to play only the game it's designed for. Galaxian, for example, couldn't draw a circle or plot a graph. It can only draw aliens! However, it can do it in real-time, to give the smooth movement and quick action that the game needs. As a budding home computer programmer in the early 80s, it was a source of frustration to me that I couldn't match the graphics performance of the games I saw in the arcades, using a home computer's general-purpose graphics capabilities. Decades later, now I can understand why! Chris
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2nd Oct 2017, 11:25 am | #26 |
Nonode
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Re: Old arcade games
By way of example, here's a picture of the circuit board from the classic Atari game 'Missile Command', dated 1979. You can see the sheer number of TTL chips involved. This game is actually rather unusual because it has (more-or-less) a general-purpose bitmapped display, but it happened to be on my desk
Chris
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3rd Oct 2017, 2:36 am | #27 |
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Re: Old arcade games
That is a very lovely pcb !
One other thing I could have mentioned in my last post, is that the way the old arcade games played also had a lot to do with the player interface. In pong for example it was two Allen Bradley 5k pots with large knobs. In Tank it was a dual control handle pairs. When these games are adapted to computers the Joystick interface is often hopeless compared to the original Arcade system. It can be worse... I was contacted by a fellow coding a Pong game into a PIC microcontroller for use with an LCD screen. He had read my paper on how Pong worked, but he was baffled about one thing.....what was it that controlled the speed of the paddles ? So I explained it was the speed that the player themselves rotated the physical control pot which related to the skill of the player. That was a shock because all he had for the interface were two up-down buttons to move the paddles and no pots. So not only are there many deficiencies in the way many original Arcade games get coded that don't match the functionality of the original game, the player interfaces are not the same either. |
3rd Oct 2017, 9:22 am | #28 |
Octode
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Re: Old arcade games
I haven't a clue with computers, but I love old video games.
I met an enthusiast once, and asked him how I would go about learning to build-up JAMMA cabinets with original boards. He said "First of all, you need to start in the '80s..." |
3rd Oct 2017, 10:07 am | #29 | |
Nonode
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Re: Old arcade games
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Chris
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3rd Oct 2017, 10:10 am | #30 | |
Nonode
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Re: Old arcade games
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Getting the original boards working properly can be a proper challenge, though. Chris
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4th Oct 2017, 1:06 am | #31 |
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Re: Old arcade games
The circuit in Atari pong consisted of 3 transistors in a set-reset configuration, the "antenna" was simply connected to the transistor's base, there was no base resistor, just diode backwards across the BE junction, so the collector-base leakage charged the b-e junction up and it sat just below the threshold where there was any significant collector current. Then if a static discharge occurred, or a burst of RF, it immediately reset the game.The circuit is described in the article I posted above.
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4th Oct 2017, 12:40 pm | #32 |
Nonode
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Re: Old arcade games
That sounds like what we used (unfortunately, all the paperwork I had on this disappeared about two divorces ago).
Being so long ago, the fine details are lost in the memory fog, but I have a vague recollection that we were supposed to wire them into the credit switch circuit somehow. The little pcb, which I think was about 1/2" by 3/4", was stuck to the coin door with double-sided tape. We used to install them into everything - pinballs, table-tops and uprights. Terry |
4th Oct 2017, 1:31 pm | #33 |
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Re: Old arcade games
I've attached the circuit of the one used in Pong.
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5th Oct 2017, 2:45 am | #34 |
Nonode
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Re: Old arcade games
Thanks Argus25.
I did have a quick look at your PDF, but I will save this for future reference. Haven't done any Game/Pinball servicing in a while now, other than a mates Firepower pinball that needs some TLC. Terry |
24th Oct 2017, 1:00 am | #35 |
Tetrode
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Re: Old arcade games
The other thing that needs to be considered with these games is that there are several revisions of each game. For Instance I have different revisions of the pong pcb design. Each revision had a specific purpose. As an example it was possible to allign the paddles so that the ball would bounce for ever back and forth. Atari wisely revised this to maximise the collection of coins over time. There are others examples suchs as the unreachable zone at the top but it's not well documented.
Atari was an amazing company that in my opinion broke barriers that Apple only really managed to scratch, Jobs imitated Nolan Bushnell and bettered him but if Nolan hadn't showed him the way Jobs would not have made a name for himself. |
24th Oct 2017, 1:36 am | #36 | |
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Re: Old arcade games
Quote:
http://www.worldphaco.com/uploads/ARCADE_MINI-PONG.pdf |
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