800xl/1200xl ram question

[Donbot5000]

I have a 800xl with red screen issues but i have silly question as im new to ataris.

can i use the 1200xl ram in the 800 to test the ram chips?

 

 

[Donbot5000]

should have specified i also have a 1200xl

[+Nezgar]

I think they should be interchangeable most of the time. They should just be 4164 types or compatible. Supposedly 4164-15, 2164-15, 4564-15, 6665-15, or 3764-15 are all interchangeable.

 

Check your ANTIC chip part #'s:

• C012296 (older) has a 7 bit refresh counter and works only with 64Kx1 DRAM with 128 cycle refresh. (2ms)
• C021697 (newer) has an 8 bit refresh counter and works with both 64Kx1 DRAM with 128 & 256 cycle refresh. (4ms)

If both machines have the same ANTIC p/n, you should good. If not, you might need to also swap the ANTIC for stability depending on the matching RAM.

 

Red screen can also mean dead OS ROM. You cannot swap OS ROM between 1200XL (2x 8KB ROM) and 800XL (1x 16KB ROM). Conveniently, the 800XL OS ROM chip can be directly replaced with a 27128 EPROM programmed with the equivalent OS.

[Donbot5000]

Thanks this should help me troubleshoot my 800xl. i inherited several Atari computers and will need help with several of them especially the Stacy 2 .

I think they should be interchangeable most of the time. They should just be 4164 types or compatible.

 

Check your ANTIC chip part #'s:

• C012296 (older) has a 7 bit refresh counter and works only with 64Kx1 DRAM with 128 cycle refresh. (2ms)
• C021697 (newer) has an 8 bit refresh counter and works with both 64Kx1 DRAM with 128 & 256 cycle refresh. (4ms)

If both machines have the same ANTIC p/n, you should good. If not, you might need to also swap the ANTIC for stability depending on the matching RAM.

[Donbot5000]

so the 1200xl has the 96 antic chip and the 800xl has the 97 antic chip . im going swap the antic chip and ram and see if that makes any difference i did also reseat most the chips on the 800

 

it not too big loss if my 800xl doesn't work as i can use its power switch for parts for my 130xe as i prefer its aesthetic anyway (i know thats not a popular opinion).

[+Nezgar]

Some cheap sources for RAM I linked to in another recent thread: http://atariage.com/forums/topic/282180-atari-800-xl-black-screen/?p=4097663

 

These types of failures seem common on the forum here, I'm sure with the help of the folks here you can figure it out!

 

(And I personally prefer the 130xe look, so you're not alone but I definitely appreciate the XL's more for for modding and troubleshooting due to the extra space inside and sockets!)

[Donbot5000]

Some cheap sources for RAM I linked to in another recent thread: http://atariage.com/forums/topic/282180-atari-800-xl-black-screen/?p=4097663

 

These types of failures seem common on the forum here, I'm sure with the help of the folks here you can figure it out!

 

(And I personally prefer the 130xe look, so you're not alone but I definitely appreciate the XL's more for for modding and troubleshooting due to the extra space inside and sockets!)

Im plan on adding socket's to my 130xe and what other mods should i do ?

[SS]

This is exactly the type of issue that the SYS-CHECK was made for.

[+DrVenkman]

This is exactly the type of issue that the SYS-CHECK was made for.

 

 

Sure, but getting a Sys-Check requires time, money and the vagaries of international postage. Swapping chips is a tried-and-true method that will detect or narrow down a hell of a lot of basic issues. Adding in a scanned service manual, a multi-meter and a logic probe and you can identify almost any issue, no external PBI device needed. Even better, those skills will translate to the 400/800/1200XL machines, as well as most vintage game systems.

 

And I don't say that to belittle the Sys-Check - I have one on my "I ought to buy one" list myself. But it's on there along with a lot of other stuff.

 

Your mileage may vary of course.

[+Nezgar]

so the 1200xl has the 96 antic chip and the 800xl has the 97 antic chip . im going swap the antic chip and ram and see if that makes any difference i did also reseat most the chips on the 800

After this swap, if the 1200XL still works, you know the RAM is good in both machines, and the problem is elsewhere in the 800XL. (don't call it an 800, as that is actually another older Atari computer, which could lead to confusion )

[shoestring]

Could also be a dead MMU

Edited September 1, 2018 by shoestring

[Donbot5000]

ok so i dont have psu for the 1200xl yet but when i swapped the chips into the 800xl (sorry forgot about the 800) the 800 xl had no change so either there are bad chips int he 1200 too (totally possible as its in poor condition) or something else is bad.