$2,500 800 on eBay...

[$2,500 800 on eBay...]

Based on the pictures in this auction, it appears that the auction the op posted is simply the box that goes inside the colorful sleeve. 

 

https://www.ebay.com/itm/Atari-800-home-computer-system-48K-Ram-With-Original-Box-UNTESTED/133384720606?_trkparms=aid%3D1110001%26algo%3DSPLICE.SIM%26ao%3D1%26asc%3D225086%26meid%3Dd3d54085d5434ad5b48063ca5bc2ccae%26pid%3D100623%26rk%3D4%26rkt%3D5%26sd%3D402134754048%26itm%3D133384720606%26pmt%3D0%26noa%3D1%26pg%3D2047675&_trksid=p2047675.c100623.m-1

[Question about light switches]

7 hours ago, scotty said:

Trying to make a Pole position controller for Mame on the cheap...  As cheap as possible for a proof of concept.   As far as a gear shift, being that is just high and low, is there any reason that a standard home light switch wired to an encoder do the trick?

 

 

Also, wouldnt a light dimmer switch connected to an analog encoder work for pong paddles?

 

The light switch would work fine for the gear shift. The dimmer is a little more complicated. There is more electronics in a dimmer then just the potentiometer (variable resistor)  so hooking it up directly would not work. You could potentially use the potentiometer inside, but it would have to be the same resistance value as the one in Pong. 

7 hours ago, scotty said:

 

 

[Noob seeking advice]

36 minutes ago, 2600Ibarelyknewher said:

I’m looking to replace the capacitors on two Sega game gears I own. Both are VA5-837-10766 motherboards, I have compiled a list of parts from mouser to complete the task. I’m no expert but this is what I have compiled from mousers website.

https://www.mouser.ca/Cart/

Let me know your thoughts, it seems like they all should be right for fitment on the board and the ratings of the capacitors themselves.

That link will only show you your cart, no one else can see it.

[Atari Not the First! The History of Mechanical Pong Games]

I ran across this video the other day that shows the inner workings of Blip. Really cool piece of mechanical design...

 

 

[RCA Studio II not working]

On 4/17/2020 at 8:17 PM, BurgerWeeze said:

Update:

I resoldered every single pin but it changed nothing... Still get the same corrupted picture

I've also checked the diodes, all good. Next up I guess I'll try switching out caps... once I can get my hands on some parts.

Did you check if you are getting a good voltage from the power supply?

[RCA Studio II not working]

Since you are getting something on the screen the analog portion is probably working ok, so video is getting from the video chip to the TV, so this would leave a problem with the digital part of the system. In any other system I would say start with cleaning the cart connector, but since the internal games don't work either, that's not going to be an issue. If you have soldering skills you could try touching up solder joints. 

[Old pictures of our Atari 8-bit setups]

9 hours ago, adam242 said:

Wish I (or my parents) could find an old pic.. my setup was a 130XE and monitor on the far right of the desk (same desk I'm using today!) with two 1050s and Supra modem stacked in the middle to the left, and a generic Centronics printer and 1020 on the far left. Can still see it clear as day.

 

If you were using a non-Atari printer with the 850 interface module, it made sense to have the printer on the left since the parallel jack on the 850 was on the left, although I easily solved that problem by flipping the 850 upside down.

[Anyone have an Epson HX-20?]

I never had one personally, but back in the 80's my Dad brought one home from work along with a digital scale and we worked on interfacing the computer to the scale to do data collection. 

[Old pictures of our Atari 8-bit setups]

18 hours ago, Keatah said:

Interesting and amusing how most of us kept our printers to the righthand side of the setup.

It's interesting that you mention that, because despite what is shown in my picture, I distinctly remember having the disk drives on the right. Being right handed it I think it was just easier. In that picture I don't have the printer on a stand so I had to have it on the right so there was room on the floor for the paper. We eventually created a simple stand for it by putting dowels in the screw holes on the bottom to create legs. I think at that point I switch sides.

 

My Dad custom built that desk. Notice the custom made shelf for the 850 interface right under the TV.

[Old pictures of our Atari 8-bit setups]

17 hours ago, Max_Chatsworth said:

Is that....is that a drawing of you right behind you?  How recursive...

It's actually one of those computer printed portraits you get done at a kiosk in your local mall back then. 

[Old pictures of our Atari 8-bit setups]

Me and my 800 from July of 1982. 

[Very Early Digital Photography]

11 hours ago, ClausB said:

There were magazine articles about making a digital camera from a decapped RAM chip (ceramic chip with metal cap removed) that was photo sensitive.

Yeah, a dynamic RAM cell actually behaves a lot like a pixel in a modern CCD, so they were used in early video camera. There was a camera that used this technique demoed at last years VCF east. You can see it in this video...

 

https://youtu.be/krSurGeloEo?t=182

[Very Early Digital Photography]

I definitly remember these kiosks! Here is a picture of me from back in 1982 at my Atari 800 with one of the computer printed pictures of me on the wall. 

[Funny bug in 1020 firmware]

2 hours ago, Rybags said:

Seems to be no dump of the firmware around.

From a Hackaday page I got a link http://www.buildlog.net/blog/2019/10/inktober-project-2019-post-5/

 

It seems to do 3 stepper motor iterations for each pen change, so there's probably some slightly more complex operations on the parameter to obtain the result.

There used to be a web site that had a lot of the Atari 8-bit firmware, but I can't seem to find it now. Don't remember if they had the 1020 firmware, but they had it for a lot of the peripherals. 

[What was the first system you programmed?]

The first system I programmed was my Atari 800 in Basic. I had two neighbor friends, one had a TRS-80 and the other an Apple 2, and we were all interested in programming so we all worked together to write programs. We actually submitted two to Softside Magazine's 1K program column, although neither was accepted. After Basic I eventually moved to Action!.

 

I tried my hand at assembly but never got the hang of it. When I went to college I had a 6502 assembly programming class where we used the AIM65. I then got a job as a hardware technician at a company that manufactured data communications equipment a lot of which was based on the 6502, so even despite my struggles with it on my Atari 800, I eventually became very proficient in 6502 assembly. 

 

After the 800, I got an Atari ST and start using GFA Basic which I eventually used on the PC before selling my soul to Microsoft when I start with Visual Basic 1.0. 

[Adventure Construction Set]

Thanks to James Read who made numerous improvements in the 2.0 version. Here are some of the highlights. See the release notes file for a full list.

 

• Support for Amiga and Apple II files
• Store contents are now accurate
• Palette colors and names now accessible from graphics viewer
• Can view players saved with the game
• A number of improvements to the room viewer
• All graphics are now shown in the graphics viewer

You can get the new version from my web site 

http://atarihq.com/danb/acs.shtml

[early tia chips: 2 or 3 sprites?!?!]

Very interesting page, I had never seen it before. 

[Extended RAM bank?]

On 6/18/2019 at 4:42 PM, Mux said:

WRT bits -vs- bytes.. It's still mapped as a byte but, as pointed out earlier, some bits don't physically exist. Usually they're marked with an 'x' or '-' or something similar. Think of it as having 4 wires on a bus rather than 8. The non-connected wires contain 'junk' as well, they're not connected.

 

The copy mode is supposed to help you speed up updating VDP registers although I don't really see the advantage as it's still a MOV instruction. I guess it helps you don't have to switch back and forth.

 

-Mux

As you say, the savings comes from not having to switch back and forth. Since external RAM and the VDC cannot be on the bus at the same time, you would have to switch back and forth for every byte which saves a lot of instruction cycles. 

[Odyssey 2 programming - using numbers in a table]

2 hours ago, atari2600land said:

So how would I move #randomness into r6 then?

 

MOV A,#randomness

MOV R6,A

[Odyssey 2 programming - using numbers in a table]

On 2/9/2020 at 10:47 PM, atari2600land said:

So I have this:

 

randomtrack1:
    db  0a0h, 0f0h, 0f0h
    
randomtrack2:
    db  0f0h, 0a0h, 0f0h
    
randomtrack3:
    db  0f0h, 0f0h, 0a0h

tracknum:
    db    randomtrack1 & 0ffh
    db    randomtrack2 & 0ffh
    db    randomtrack3 & 0ffh   

 

 Each randomtrack data represents a sprite being on screen. If the value is f0h, then it's not on screen, but if it's a0h then it is. I have this variable called "randomness" that I'd like to put into a code that pulls the number of tracknum that is the value of "randomness" (0, 1, or 2.) So I started to do that. I have this:

 

    mov r0,#randomness
    mov a,@r0
    mov r6,a        ; randomness now in r6
   
    add a,#tracknum & 0ffh    
    movp a, @a ;get byte

    mov r1,a
    
    mov r0,#000h
    mov r7,#1
    call copyspriteloop3   

...

 

 The problem is, I don't know what to do with r6 after I moved randomness into it. All I get if I put this in there is a pattern that keeps repeating over and over again, which isn't what I want to do at all. Help me, please.

 

It's been a while since I have worked with the 8048, but I think you have a problem right away with this code:

 

 mov r0,#randomness
    mov a,@r0
    mov r6,a        ; randomness now in r6

Lets says randomness = 2. The first line moves 2 into R0. The second line gets the value in RAM that is at the address stored in R0, so in this case if will get whatever is stored in memory location 2 which is also R2. Line three moves that value in to R6. So randomness wouldn't end up in R6.

[Box Art Discussion]

On 3/31/2020 at 2:13 PM, Zoyous said:

The Sega Master System gets a lot of criticism for its early box art but it's also got some excellent art, especially in the later years. Take a look at this box for Air Rescue. Whoever painted this went to town. Aside from the properly intense composition, they've literally painted every single bolt on the helicopter, the person clinging to the rope ladder for dear life as it crazily twists and bucks in the wash from the chopper blades is wearing incredibly detailed tattered and spattered clothes, and the guy holding the ladder is encouraging him every rung of the way to safety - watch your thumb with those chopper blades, buddy!

 

I can't imagine why something like this would get criticism. ;)

 

[Box Art Discussion]

I have always been a fan of the Hard Hat Mack cover art. One of the few games I can think of that had a real photo graph as the cover instead of something drawn.

 

[FS: Vintage Cartridge Storage]

Bump

[FS: Vintage Cartridge Storage]

I have the cartridge storage items pictured below for sale. They are in pretty good condition except for the one with the lid which has a big crack in the lid. Vintage dust included at no extra cost. :)

 

Private message me if you are interested. Not looking to get a lot for them, so make me an offer.

[Atari in the News - Cool BBC Article!]

This sort of reminds me of the algorithm the Telengard uses to generate it's maze. It uses a algorithm based on your current location in the maze and three hard coded constants. They must have had to hand tune those constants until they got acceptable mazes. You can read the details here:

 

http://atarihq.com/danb/Telengard.shtml