Atari 800XL RAM

[c1ph3rpunk]

Looking for RAM chips for my 800XL, currently has the MT4164-15 chips in it. ANTIC is C021697-11, I’ve read that one needs 256 cycle refresh but have also read it can use 128, is any of that true?

 

The ones I’ve been looking at are:

 

KM4164B

MN4164P-15A

 

Both appear to be 128, it looks like only the MT ones are 256?

 

Looking for any currently known reliable sources or eBay sellers, the ones I’ve seen on eBay that list 25 of them for $10 (from China) I’m immediately suspect of.

 

/TIA 

[Beeblebrox]

I've used oki, Mostek and Hitachi chips in the past.

 

See also here:

 

Just looking on ebay.co.uk

 

https://www.ebay.co.uk/itm/323810100147

 

1 PC. MK4564N-15 64K x 1 Dynamic Ram Mostek (United Technologies Mostek)

 

I am sure you can find US based suppliers for these and other equivalents. 

 

 

[ACML]

eBay:  Samsung 64Kx1 DRAM 128ns refresh at $1 a piece.  They work great in my 1200XLs.  I have the early ANTIC CO12296, but CO21697 should work with either 256 or 128 refresh.

https://www.ebay.com/itm/394196650992

 

[c1ph3rpunk]

1 hour ago, Beeblebrox said:

I've used oki, Mostek and Hitachi chips in the past.

 

See also here:

 

Just looking on ebay.co.uk

 

https://www.ebay.co.uk/itm/323810100147

 

1 PC. MK4564N-15 64K x 1 Dynamic Ram Mostek (United Technologies Mostek)

 

I am sure you can find US based suppliers for these and other equivalents. 

 

 

I thought there had to be a thread around for this, didn’t find this one, thanks.

 

I’ll search for the MOSTEK one, my father worked there in the late 70’s, nostalgia, big time. Dad didn’t like LJ Sevin much, said he taught me how to flip him off, “what’s he gonna do to a 7 year old, fire you?”

[c1ph3rpunk]

50 minutes ago, ACML said:

eBay:  Samsung 64Kx1 DRAM 128ns refresh at $1 a piece.  They work great in my 1200XLs.  I have the early ANTIC CO12296, but CO21697 should work with either 256 or 128 refresh.

https://www.ebay.com/itm/394196650992

 

Does using the 128 instead of the 256 bring any sorts of performance implications? I’m guessing it just cycles twice with the 297 ANTIC.

[Beeblebrox]

Most of my ram chips are either 12 or 15. Occasionally 10. I've not really noticed much of a difference in terms of performance. 

 

Thinking about it I've used the Samsung chips as well. 

[thorfdbg]

34 minutes ago, c1ph3rpunk said:

Does using the 128 instead of the 256 bring any sorts of performance implications? I’m guessing it just cycles twice with the 297 ANTIC.

No. Either they work, or they don't. The timing is up to the computer to make, the RAMs don't have a word to say how fast they are addressed. You will notice if they cannot match the speed of the system.

[ClausB]

12 hours ago, c1ph3rpunk said:

ANTIC is C021697-11, I’ve read that one needs 256 cycle refresh but have also read it can use 128, is any of that true?

That newer ANTIC works with either 128 or 256 cycle refresh RAMs.

[c1ph3rpunk]

1 hour ago, ClausB said:

That newer ANTIC works with either 128 or 256 cycle refresh RAMs.

Perfect. Thx.