Re: Laser 128 - 1MB Memory Exansion Card - Question?

["Laine Houghton" <laine@intergate.com>]

"Robert Steinmetz" <not-rsteinmetz@mindspring.com> wrote in message
40828B75.4050405@mindspring.com">news:40828B75.4050405@mindspring.com...
> Willi Kusche wrote:
> > Hi!
> >
> > Robert Steinmetz <not-rsteinmetz@mindspring.com> wrote in message
news:<4080CA65.1090503@mindspring.com>...
> >
> >>I have a 1MB Laser 128 Memery Expansion Card. It has 4
> >>banks of memory (8 chips per bank) of which only one
> >>is populated. Although I have the original box I don't
> >>have the original documents.
> >>
> >>Can some one confirm the requirements for memory to
> >>populate the remaining 3 banks?
> >
> >
> >     There's a high probability that it uses 41256 chips.
> >
> > Willi
>
> I've pulled the cad and the chips are HM502560-15. As
> far as I can tell this is 1x256k chip and I have room
> for 3 more banks of 8.
>
> Can someone please provide more information on this
> chip and a source for them?
>
> Is this chip compatable with any other common chips?

When I scanned the section of the laser 128 manual on the 1 meg board it
said to fill it with 41256 chips.

Any 256k x1 dram chip (-15,  150 ns) or better should work.

I question your last '0'. They did have 6P, 6C, 6G.
The HM50256 is an Hitachi 256k x 1 dram memory chip.