[Images generated by RastaConverter]

11 hours ago, Stephen said:

Best I could manage - 75 colours.  There's just not enough resolution to really pull any details here.

Stephen_StarshipLaunch.xex 22.15 kB · 3 downloads

Thanks for the effort. I think it looks pretty good; maybe the sunrise needs a little fixing.

[Confused about Atari 8 bit (XL/XE) graphics modes]

The A8's display list is a unique concept. Each scan line can be a different graphic or character mode. C64 doesn't have that.

 

The A8's indirect color registers allow dynamic color changes from a wide palette without rewriting bitmaps. C64 doesn't have that.

[Images generated by RastaConverter]

Request: SpaceX Starship launch: 

[Atari 65XE (130XE) -> 329kb memory upgrade]

On 2/20/2023 at 5:43 PM, ClausB said:

256Kx4b, have 20 pins and are not pin-compatible. Worse still, they need 9 bits of refresh address, and ANTIC supplies only 8. You might consider installing a modern SRAM upgrade instead.

All the 44256 chips I've seen need 512 refresh cycles (9 bits). They won't work without extra circuitry to generate the extra bit. Good luck finding 256Kx4 chips with 256 refresh cycles.

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Request: album cover: Dark Side of the Moon

[Clear plastic case for the Atari 800]

8 hours ago, Geister said:

Plexiglass puzzle-piece cases will never "resemble" the original cases.

Could they make a decent case for a 400, which has all flat sides?

[Replating the card edge connectors on some old cartridges that still work otherwise...]

Very thin coat of solder might work. Older RAM boards were 'tinned' this way. They do corrode more quickly than gold and need reseating or cleaning, but carts get swapped in and out more often than RAM.

[Atari 800 video upgrade]

I don't recall. Maybe we used whatever FJC's video recommend.

[I made a keyboard for my 400Mini...]

[Books about 3D graphics programming for the '80s home computers?]

A little 3D wireframe animation:

 

 

[First game to play on the 400Mini]

Star Raiders! Oh, wait...

[Alternate History: What Atari Could Have Done Differently?]

They might have lowered prices on the 400 and 800 sooner to slow the success of the VIC20.

[800 XL with Bad Memory -- Will U1MB upgrade fix this?]

21 minutes ago, olix said:

Did I understand correctly that the number of reresh cycles (128 or 256) only plays a role with DRAMs?

So if I use a 64K extension with SRAM, like the one from Lotharek, it shouldn't matter whether I use the older ANTIC with 7-bit refresh counter or the newer one with 8-bit refresh counter? Is that right?

Yes. It doesn't matter unless you're replacing faulty DRAM chips.

[CPM/Z-80 card for the 1090XL -- Calling anyone with Z-80 experience!]

Could they be Freddie chips?

 

Or maybe PIA chips for banking?

[800 XL with Bad Memory -- Will U1MB upgrade fix this?]

6 hours ago, olix said:

How do i know, if the ram is a 128 or a 265 cycle refresh type?

Gotta look at the data sheet.

[800 XL with Bad Memory -- Will U1MB upgrade fix this?]

9 hours ago, BrainSlugs83 said:

er... Wouldn't that make 256 cycle dram more compatible? -- i.e. a 256 cycle chip on a 7-bit refresh counter would just cause the dram to be refreshed twice as often as it needed (and that would be fine and in spec), but if you used a 128 cycle chip on a newer machine that happened to have an 8-bit refresh counter... it would be refreshed only half as often as it needed to be? (i.e. you could use a 256 cycle chip anywhere, but a 128 cycle chip would only work on a machine with a 7-bit counter?)

No, the 7-bit ANTIC would only refresh half of a 256 cycle DRAM, so the other half would fail.

[800 XL with Bad Memory -- Will U1MB upgrade fix this?]

5 hours ago, BrainSlugs83 said:

I've read that some of the chips have a refresh of 128 or 256 cycles and that 256 cycle refresh chips are more compatible... Is that still considered true?

128 cycle 64K DRAM chips are more compatible because some 800XLs have the older ANTIC with 7 bits refresh addressing.

[Help with strange graphic glitch on my A800]

13 hours ago, Rybags said:

It looks like it gets stuck on luma value 8.

 

Try in Basic:

 

SE. 4,0,4

SE. 4,0,8

SE. 4,0,10

SE. 4,0,12

 

Possibly the 4050 which processes the luma outputs is faulty.

The photos show it's stuck on luma value 9. I doubt it's the 4050. More likely it's saturated luma at the HDMI converter which is expecting a lower voltage range than the 800 provides.

 

A simple test to vindicate the 800 is to try the RF output on a TV which accepts the old analog standard.

 

A possible workaround is to wire a pulldown resistor to the 800's luma output. Maybe 75 Ohms to ground.

[Help with strange graphic glitch on my A800]

Have you tried adjusting contrast and brightness on the monitor? It appears that the luma signal is saturated.

[Atari 800 Solid White Screen]

Any luck with this? Another trick we use with those tinned card edge connectors is to run an eraser over them to remove the dark corrosion.

 

Looking forward to seeing it on your excellent YT channel.

[Just got an Atari 400: What type of limitations will I run into other than the 16kb of RAM?]

12 hours ago, RockLobster said:

Attached is a photo of the atari8bit cartridges I have.  

Get Star Raiders or go home!

[So how did you get your first 5200?]

Required accessories:

[Atari 8-bit machines comparison table]

Can I argue that the 400 keyboard does have slight tactile feedback? Raised key edges help the finger locate. Speaker click is felt in the fingertip.

[If the 5200 is just an Atari 8 bit computer in console format is there some way to play Atari 8 bit family games on it ?]

Here is a technical article about the differences.

https://atarihq.com/danb/files/52analog.txt

 

[So how did you get your first 5200?]

eBay baby!

4-port with no PS switch box nor controllers. Had to clean it up and modify it to separate power and RF.