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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: 23703jim on April 08, 2006, 05:17:22 AM

Title: How many does it take?
Post by: 23703jim on April 08, 2006, 05:17:22 AM

on the right side front of the motherboard a3000 desktop there are a whole bunch of sockets for memory chips. i feel that if i fill them all i would have 16 megs of memory?
but can i just use a few how many? say i filled half of the sockets with this memory. could i do that? please advise i have a few of these chips but not enough to fill
up all the sockets. thanks again so much :-?

Title: Re: How many does it take?
Post by: Kin-Hell on April 08, 2006, 09:08:46 AM

Depends on the size of your Zip Chips.
If you fill them all with 1M×4 Zip Chips, you will have 16Mb (16 Sockets)
Fill them all with 256k×4 80 ns DIPs, you will have 4mb, but these must be done in groups of eight, thats one entire bank.
However, all the banks have to have the same sized/type of chips. The RAM chips can be either static column or page mode ones. Static column Zips are 10% faster & support burst memory access.
The 8 Sockets under the Fast Ram sockets are to add another 1Mb of Chip Ram via 44256k 120 ns DRAM DIPs, just in case you only have 1Mb Chip Ram in your rig, & that 1Mb is Soldered to the Mobo.
Cheers!  :-)

Title: Re: How many does it take?
Post by: Zac67 on April 08, 2006, 09:14:09 AM

23703jim wrote:
>on the right side front of the motherboard a3000 desktop
>there are a whole bunch of sockets for memory chips. i feel
>that if i fill them all i would have 16 megs of memory?

Yes.

> but can i just use a few how many?

Yes, they need to be installed in sets of 8 for 4 MB (1Mx4 chips).

>say i filled half of the sockets with this memory. could i
>do that? please advise i have a few of these chips but not
>enough to fill
>up all the sockets. thanks again so much :-?

Note: all chips must be the same type, either 256Kx4 (e.g. 514256) or 1Mx4 (51440x) and either fast page (..00) or static column (..02). They're organized this way:
4 4
3 3
2 2
1 1
4 4
3 3
2 2
1 1
4 4
3 3
2 2
1 1
4 4
3 3
2 2
1 1

so first you fill the '1' sockets, after that the '2' sockets and so on.

Title: Re: How many does it take?
Post by: amigagr on April 08, 2006, 09:18:48 AM

Quote

Zac67 wrote:
so first you fill the '1' sockets, after that the '2' sockets and so on.

yes that's right, here (http://users.hol.gr/~amije/) you will find some images on how they are organized these 4 banks and an example of 8mb ram on board (16 chips)