[net.micro.amiga] Expansion RAM on Amiga

peter%gumby@gumby.UUCP (04/25/86)

Can anyone tell me how difficult/easy it is to add RAM to the
Amiga after the first 256K expansion?

For instance, are all dynamic ram control signals available
on the bus (row select, column select, refresh, ...) or do
some signals have to be derived externally? If these signals
are available why are commercial expansion board so expensive?
With current mail order price using 256K x 1 DRAM it should not
cost more than U.S.$170 for 1.5 mega-byte of chips.

I'm asking this because my dealer doesn't have the hardware
manual in stock and I want to know if I can expand my Amiga
to 2 meg myself.

peter
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randy%cbmvax@cbmvax.UUCP (04/26/86)

In article <288@gumby.UUCP> peter@gumby.UUCP (Peter Wu) writes:
>Can anyone tell me how difficult/easy it is to add RAM to the
>Amiga after the first 256K expansion?
>
>For instance, are all dynamic ram control signals available
>on the bus (row select, column select, refresh, ...) or do
>some signals have to be derived externally? 

  The custom chips control/make available the dram control 
signals -- but ONLY to the first 512k bytes. Beyond that, you
have to add your own.

>With current mail order price using 256K x 1 DRAM it should not
>cost more than U.S.$170 for 1.5 mega-byte of chips.
>

Add to that the cost of an enclosure, extra power-supply (if needed),
plus additional circuitry to allow auto-configuration. And, to 
add to the Amiga expansion bus, you then have to decide whether to 
pass the buss along, or not. And so on...including being the first
on the block. How expensive was/is IBM expansion memory until
3rd. party boards appeared on the market?

-- 
Randy Weiner -- Commodore Business Machines <<Amiga Technical Support>>
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