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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: motrucker on June 22, 2012, 08:59:46 PM

Title: 2091 ram
Post by: motrucker on June 22, 2012, 08:59:46 PM
I have a 2091 card with 1Mb of RAM installed. It isn't showing up (plenty of room ram wise) the RAM chips are in the 3rd & 4th banks (as opposed to the 1st and 2nd bank). Will that create a problem?
The SCSI works fine, it's only the RAM that gives me an issue.
Title: Re: 2091 ram
Post by: Azryl on June 22, 2012, 09:47:16 PM
Hiya, I believe there are jumpers you need to set for 1meg of ram in the "first" bank, so yeah you should move the ram into the first 8 sockets.

Have you read the Amiga hardware pages about jumper settings?

Big Book Amiga Hardware

http://www.amiga-hardware.com/showhardware.cgi?HARDID=1161

Amiga Resource

http://amiga.resource.cx/exp/a2091


hope this helps!

Az
Title: Re: 2091 ram
Post by: mechy on June 22, 2012, 09:49:31 PM
Quote from: motrucker;697572
I have a 2091 card with 1Mb of RAM installed. It isn't showing up (plenty of room ram wise) the RAM chips are in the 3rd & 4th banks (as opposed to the 1st and 2nd bank). Will that create a problem?
The SCSI works fine, it's only the RAM that gives me an issue.

The 2091 needs 256x4 chips(usually marked 514256, 44c256 etc or similar but there are many other #'s) .. 8 chips make 1MB.
the 2091 can take 512K,1M,2MB.. be sure to set the jumper on the card to signify what is installed.for 1 Mb you would fill sockets u14-u21 (look inside the socket for #'s)
Title: Re: 2091 ram
Post by: motrucker on June 23, 2012, 12:28:12 AM
Quote from: mechy;697584
The 2091 needs 256x4 chips(usually marked 514256, 44c256 etc or similar but there are many other #'s) .. 8 chips make 1MB.
the 2091 can take 512K,1M,2MB.. be sure to set the jumper on the card to signify what is installed.for 1 Mb you would fill sockets u14-u21 (look inside the socket for #'s)

I thought the placement was a problem, BUT none of the docs I can find say a word about chip placement. I set the jumper right, but I received the card with the RAM installed this way - so I wasn't sure.
I am lucky enough that this card has the revision 08 SCSI chip in it - thanks to another Aorg member.
btw the chips are marked "p21014 - 10" - I'll look them up later.
Title: Re: 2091 ram
Post by: mechy on June 23, 2012, 12:41:20 AM
Quote from: motrucker;697601
I thought the placement was a problem, BUT none of the docs I can find say a word about chip placement. I set the jumper right, but I received the card with the RAM installed this way - so I wasn't sure.
I am lucky enough that this card has the revision 08 SCSI chip in it - thanks to another Aorg member.
btw the chips are marked "p21014 - 10" - I'll look them up later.

On most ram cards you usually fill the lower banks and or lowest numbered sockets in order.

I wonder if some of the first ram was bad and was removed or? who knows.
the part number is a 256x4 so you should be good in that respect if the chips are good.

Mech
Title: Re: 2091 ram
Post by: motrucker on June 23, 2012, 12:46:56 AM
Quote from: mechy;697603
On most ram cards you usually fill the lower banks and or lowest numbered sockets in order.

I wonder if some of the first ram was bad and was removed or? who knows.
the part number is a 256x4 so you should be good in that respect if the chips are good.

Mech

I just switch the chips, and put the card back in - everything is AOK now.
Now this old 2000HD is up and running again. I'll take some photos and send them up. This thing is in great shape - I'm the second owner!
Title: Re: 2091 ram
Post by: Azryl on June 23, 2012, 01:58:43 AM
Awesome... glad you have a functioning Miggy... they are fun :)

Az