[comp.sys.apple] Memory Chips for GS-RAM ...

dales@pro-novapple.UUCP.UUCP (11/15/87)

To:
netnews Jock Cooper <crash!rutgers.EDU!clyde!burl!codas!killer!jockc>

>This is exactly what I did with my old Ramworks //... I bought it with 256k
>and bought 768k from MicroProcessors, Inc.  I thought I could just move
>those chips from the ramworks // to the gsRam.  It only worked partially...
>The Hitachi chips that came on the Ramworks // worked on the gsRam, but the
>768k of Toshiba chips I had previously purchased from Micro... inc. were
>reported by the ae memory test as being bad (every one).
>
>So instead of having 1.5 megs in my machine i have to settle for 768k until
>I can figure out why those Toshiba chips dont work on the gsRam, or buy
>more...
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This has become almost a classic GS memory expansion problem.  GS-RAM (and
Apple's GS Memory Expansion Card too) require RAM chips that work with the
"CAS before RAS" (Column Access Strobe before Row Access Strobe) mode of
memory
refresh.  I suspect that your Toshiba chips happen to be RAS before CAS mode
chips which is why they fail the chip test - even though, in the right useage,
they may be perfectly good.  Check your GS-RAM manual; it has a list of
acceptable chip numbers from various manufacturers:

                GS-RAM
        
        Hitachi                 HM50256-15
        Mitsubishi              M5M4256P-15
        Fujitsu                 MB81256-15
        OKI                     MSM41256A-15AS/RS
        Micron Technologies     MT1259-15
        Samsung                 KM41257-15
        Toshiba                 TMM41257-15
        Texas Instruments       TMS4256-15

This is the list for the 256K chips and, as AE notes, it is only a partial
list.

Hope this is useful... I just saw the net feed on pro-novapple.
 
Later...
                                        .dale.

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