Part swap between 400 and 800XL?

[Urchlay]

I've got a dead 800XL that's been dead a long time... it originally got fried because I was using a variable-voltage bench power supply, and someone cranked the voltage up (probably 12V or 24V, where there should only have been 5V).

 

I've also got a disassembled 400, minus the OS and RAM boards. The only thing wrong with it was the RAM was flaky (homebrew 48K upgrade).

 

I know the CPUs are different (6502 in the 400, "Sally" 6502C in the XL), but what about ANTIC, POKEY, GTIA? Are those the same parts, or do they have different pinouts, voltage requirements, etc, between the 400/800 and XL series?

 

I know the chips are probably not socketed on the XL either... I used to be pretty good with a vacuum desoldering gun, might try it anyway if the chips will actually work.

 

What all is likely to be burned out, in the XL? I don't suppose it could just be a bad voltage regulator or something? (Or was the regulator in the power supply "brick"?)

[ylph]

Pokey should be interchangeable.

 

Depending on how old the 400 is it might have the older CTIA (CO12295) chip instead of the new GTIA (CO14805) The CTIA should work in an XL too, but you probably want the GTIA anwyay.

 

The 400/800 also used an older version of the Antic chip (CO12296) vs the newer XL/XE Antic (CO21697) altough some XL's did ship with CO12296 as well, and the older Antic should work on 800XL motherboards as long as they only use 64k bit DRAM chips (some XE's use 256k bit memory chips which I believe can not be refreshed properly with the old Antic) You might have issues if your 800 has upgraded memory (most memory upgrades use 256k bit DRAMs)

[Urchlay]

Pokey should be interchangeable.

 

Depending on how old the 400 is it might have the older CTIA (CO12295) chip instead of the new GTIA (CO14805) The CTIA should work in an XL too, but you probably want the GTIA anwyay.

 

The 400/800 also used an older version of the Antic chip (CO12296) vs the newer XL/XE Antic (CO21697) altough some XL's did ship with CO12296 as well, and the older Antic should work on 800XL motherboards as long as they only use 64k bit DRAM chips (some XE's use 256k bit memory chips which I believe can not be refreshed properly with the old Antic) You might have issues if your 800 has upgraded memory (most memory upgrades use 256k bit DRAMs)

 

The 400 has a GTIA (at least, so I remember. It's been a looong time)

 

So the old and new ANTICs are pin-compatible...

 

At one time I had 2 or 3 800XLs, one of which had 256K. Not sure whether the one I still have is the 256K one or not, but it should be easy to tell by looking.

 

I wish the 400 worked... I'd swap parts from the 800XL until the 400 quit working.

[carmel_andrews]

atari never used stock 6502's in any 8bit systems, only modd'd versions like 6502a,b or c or even 65c02 (lynx)

[+warerat]

atari never used stock 6502's in any 8bit systems, only modd'd versions like 6502a,b or c or even 65c02 (lynx)

 

The original 400/800 had stock 6502's. Look at any 400/800 CPU board and you'll find the HALT circuitry as discrete logic.

[Curt Vendel]

That's correct --

 

In the XL series the "Sally" was introduced which was custom 6502, if you look at many 400/800 CPU boards you'll seen sygnetics and other generic "MOS" 6502's on them, I even have some VERY early 800's CPU boards that have actual MOS fabbed 6502's on them.

 

Be careful when swapping ANTIC's, GTIA's and such into an 800XL, the XL's used rev C's to E's in them to correct timing issues, so putting in Rev A or B chips into an XL might cause the system to green screen lockup occassionally.

 

 

 

 

Curt

atari never used stock 6502's in any 8bit systems, only modd'd versions like 6502a,b or c or even 65c02 (lynx)

 

The original 400/800 had stock 6502's. Look at any 400/800 CPU board and you'll find the HALT circuitry as discrete logic.