[sebhc] 4044 memory chips

[Carroll Waddell]

Barry Watzman wrote:

>I was probably the source of that information.  I believe that the 2147,
>4044 and MM5257 are all interchangeable to a large degree (I ***THINK***
>that they have the same pinout, and being static memory, timing, while
>significantly different, really isn't an issue).  What I'd suggest that you
>do is verify the pinout for yourself from available documentation (the
>2147's were used in several CompuPro boards whose manuals are available
>online.  I believe that the CompuPro RAM 20 used them, among other boards).
>Although even this would probably work, I would be inclined not to mix these
>chip types on the same board, or even more so in the same bank.
>
>You can do a lot better than $9 per chip by buying complete memory boards on
>E-Bay.  For example, just a couple of days ago, some (several) Seattle
>Computer products boards (16K S-100 memory boards (and it's a VERY GOOD
>S-100 memory board, by the way)) were sold on E-Bay for about $50 per board.
>While I consider that a high price for the boards (I dropped out of the
>bidding in the mid $30's), each board has thirty-two (32) 4044's, so on a
>cost per chip basis, it's under $2 per chip.  Boards using 4044's, 5257's
>and 2147's appear quite often, you just have to know what to look for.
>Basically, any S-100 static memory card with 16k or 32k per card is likely
>to use one or another of these chips (a very few of them will use 2114's or
>4045's, which are similar chips but organized 1kx4 instead of 4kx1).
>
>Barry Watzman
>Watzman at neo.rr.com
>
>
>-----Original Message-----
>From: sebhc-bounces at sebhc.org [mailto:sebhc-bounces at sebhc.org] On Behalf Of
>Carroll Waddell
>Sent: Friday, September 01, 2006 8:32 PM
>To: sebhc at sebhc.org
>Subject: [sebhc] 4044 memory chips
>
>I hope someone can answer this question. seems as though I remember 
>reading that the 2147 memory chip was the same as the 4044 chip, only 
>much faster.
>I just found a web site that has the 2147 chips for sale, but they are 
>$9 each.
>www.twobits.com/Parts/parts10.html/
>
>If someone can verify that they are the same, we might a source of chips 
>to populate the H8-1 memory boards.
>
>Carroll
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I found a pin out of the 2147 memory chips at Chip Directory.COM
They do appear to be the same as the 4044 chips.
Carroll
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