DanBoris

It probably does ,it's an easy thing to do in digital logic. This all takes place inside Maria so there is no way to tell from the schematics if this is the case. Dan

[quote name="Mitch" 1. It sounds like you have diagnosed it correctly. 2. You should be able to use what's already there' date=' just reheat it with a soldering iron. 3. Good Luck [/quote] 2. It's usually best to add some fresh solder when re-soldering connections. You can get the right kind of solder at Radio Shack or other electronic supply store. As for re-soldering tips, I will first assume you are talking about an Atari 2600. The traces and switch legs are pretty heavy on the 2600 so they take a good bit of heat to melt the solder. If you have a low-watage iron be patient and the solder will eventually start melting. Once the solder has melted apply fresh solder to the oposite side of the pin from where the iron is. To get a good solder join always remeber to touch the new solder to the pin you are soldering and not to the iron. Dan

First note that Halt on the 6502 is actually called RDY. Pulling RDY low halts the processor. According to the 6502 data sheet RDY should be pulled low during the Phase 1 time to halt processing. It shouldn't make a difference what type of instruction is executing. Dan

I assume you are talking about the 2600... Shouldn't be to hard to do this. Since you have to stuff the playfield data every frame anyway it should be pretty easy to change the scanline on which you start displaying the background objects to achieve the scrolling effect. Dan

The basic way the trackball works is that the faster you rotate the ball the higher or lower the value you read will be (depending on the direction you roll it). Dan

I have found both a 2600 Waterworld and 2600 Crazy Climber at a local flea market for $1.00 each. Dan

Be sure to carefully clean the cartridges and the cart socket on the 2600. You may also want to remove and re-insert each of the chips on the 2600 circuit board. Dan

Yes, the cart is only needed for the 400 and 800, the later models all had it built in. Other then writing your own program's the other reason you need it is to run commercial programs that are written in Basic. There were quite a few commercial programs written in Basic. Dan

I had this problem more then once back when I originally had my Atari 800. Inside the switch under the spacebar are two little copper contacts the stick up out of the circuit board on the bottom of the keyboard. When the key is up these contacts are held appart, when the key is pressed the come together and make contact. After a lot of use one of these contacts will often break off. The space bar is one of the most used keys so it tends to happen there more often then anywhere else. You could replace these contacts but you would have to salvage one of an existing keyboard. The keyboards on the 800xl and 800 are different, and I don't think they are interchangable. You might want to check with Best Electronics (408-243-6950), they carry a wide selection of Atari replacement parts. Dan

Actually, the AC adaptor is un-regulated, the voltage regulator is inside the system. Just be sure your adaptor is rated at 9VDC and a minimum oif 500ma, and make sure the tip of the plug is positive and you should be ok. Dan

To do 3D you would start with an array of point coordinates (X,Y,Z) and a list of lines that connect these points. To render the screen you would first apply the math to each coordinate to do rotation in the three directions (Yaw, Pitch and Roll), and I believe you would also apply scaling at this point. Next you would apply another formula to each point that would project the 3D coordinates into 2D thus giving you a list of 2D coordinates for each point. Finally you draw lines connecting the points together as needed. There are numerous line drawing algorithms of varying speed and complexity. Dan

The hardware is pretty much the same as the 8-bits, same major chips (6502, GTIA, ANTIC, POKEY). The big differences are: - The GTIA and POKEY are at different addresses and there is no PIA chip in the 5200. - The 5200 joysticks are analog and are read like paddles on the 8-bit - The keyboard scanning is used to read the controller keypads - The 5200 has a very small bios that is mainly used for bootup, it doesn't provide any of the services that the 8-bit BIOS provides You can get full details on the differences here: http://atarihq.com/danb/files/52analog.txt Dan

Here are a few more observations about the graphics comparsions (not that I really thing we need more).. - The off colored dots in the man (one green and one black): Assuming the programmer of the game intended to do this they would have had to overlay both of the 2600's player sprites on top of each other to get the two colors on on line. I find it highly unlikely a 2600 programmer would "waste" a sprite for such a minor graphical enhancement. - The key shapped object: This object is clearly 11 pixels in width where all the other objects (as far as I an see) are 8 or less pixels. This is consistent with the programmer using the players sprites to represent the objects since player sprite are a maximum of 8 pixels wide. To get 11 pixels would require two sprites side by side, again, why waste a sprite for such a minor enhancement. - It's also interesting that the man is multicolored in Earthworld, and singled colored in Fireworld and Waterworld. It's a little odd that they would go back to the multicolored man for the last game especially since Atari wasn't putting anywhere near as much effort into the later games as the did the earlier. Dan

I just noticed that three digit number for the first time just recently. The positioning and quality of the stamping is very incosistant so it was obviously done by hand. The only thing I can think of is that it identifies the person who either did final assembly on the unit or did the final QC on it. It may also identify a production line instead of a specific person. As for the location I could speculate that it was put there because it's un-obtrusive and there is a reasonanbly good landmark (the slot for the power socket) to identify where to put it. Would be an interesting project to collect serial number (and the three digit stamp number) from a bunch of peoples system to see if any patterns could be indentified. Looking at the serial number of my 2600A's I just relized that the first two digits are the manufacturing year, and the second two could very well be the manufacture week. Dan

This might be possible if the system was a clone of the 2600 hardware, but I have it on good authority that it isn't a clone of the 2600 hardware in this unit. The person who told me this is under an NDA so he couldn't tell me exactly how it was done. Also, a quick look at the circuit board confirms that there is not a clear speration between "hardware" and ROM on the two epoxy blobs. There are cleary controller inputs going to the one blob, and video signals coming out of the other. So if it isn't cloned hardware there are a few options to how it could work: 1. An embedded processor with custom sound/video hardware running a 2600 emulator. This seems unlikely since it would probably not be cost effective enough to get a processor with enough power to do this. 2. An embedded processor with custom sound/video running ports of the games. It's also possible that the games where put through some sort of re-compilation process to make the porting easier. 3. A 6502 running the actual game code, and a second embedded processor and custom hardware that emulates the TIA in a combination of software and hardware. Dan

LOTS of games used these modes. They where quite popular since if used properly they could give you fairly detailed four color graphics without taking up a lot of memory which was a major consideration on these systems. Dan

From the FAQ: Input: 120VAC 60Hz Output: 9VDC 500mA Polarity: Center +, Outer - Dan

The RF Switchbox Page of the schematics: http://www.atariage.com/5200/archives/sche...Switch_Low.html shows the power section. Unfortunetly the schematics don't have any of the components labeled with location numbers (C30, R21, etc) so there is no easy way to relate the components on the schematics to the ones on the board. Dan

Don't you just hate asymetric instruction sets Dan

A. Yes, these are disc capacitors B. Not necessarily. If the black is glossy then it might be a painted on marking. If the capacitors where fried it would be a duller burnt look, not shinny black. C. Possibly, but as I said in B it might not be the case. It's more likely that it would have blown out the voltage regulator in the 5200. Dan

You can find a list of all the 2600 cart sizes here: http://www.tripoint.org/kevtris/files/sizes.txt Dan

It appears that Activision did some conversions from the 2600 to the 5200 in this way. Kaboom for example is one of the few 5200 games that uses the direct writes to the player graphics registers. I image they did this as an easy way to port from the 2600 to the 5200. Dan

From the persepcitve of todays gamer the original Castle Wolfenstein would be considered an obscure prequel to the Wolfenstein first person shooter, but as the previous poster pointed out Castle Wolfenstein was a very popular game back in the day. Dan

Most of the ROM sites that have gone underground provided ROMS for newer systems from companies that are still doing a lot of business, like Nintendo and Sega. It's these big companies that have pushed the ROM sites underground. Dan

Part of the reason for the poor 7800 homebrew scene probably has to do with the steep learning curve for the 7800 hardware. The graphics hardware is much different then the 2600 and 7800 and it's isn't real obvious on the first (or second, or third..) read of the tech documents how to use it to produce a game. Also, up until about a year ago there was no way to produce the security key needed for the carts to run, so people probably avoided jumping into homebrewing. Dan