Help with C= 2091 SCSI memory upgrade

Tajmaster

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Hi all

I have a Commodore 2091 SCSI card with no RAM onboard. I also have a Supra RAM card:

http://www.amiga-hardware.com/showhardware.cgi?HARDID=1078

This has 2MB onboard. Can I take the little chips out of this and put them in my 2091? Is it easy to do? Or should I just but the right chips for my 2091?

Thanks in advance

Taj

EDIT: The Commodore card has v6.1 ROMs if that makes any difference.
 
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rkauer

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Not possible.

The A2091 use 256kb x 4bits chips.

The Supra use 1M bit x 1 bit.
 

Tajmaster

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Ahh, thanks for the info rkauer :)

Are the chips for the 2091 hard to come by? I was thinking if its just a few quid for them then I might as well upgrade it.

I think there is a later ROM version too, V7 if Im not mistaken, are these hard to come by too?

Ive already got a GVP in my main A2000 but I thought Id try do what I can with the hardware that I have :)
 

rkauer

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Not at all.

They are pretty common but may cost you. I bought a pair from a street electronic store who charges me R$10,00 for each chip(!) ( ~£3.50). What a robbery!:mad:

A few weeks ago a friend gave me other 12 of those chips...

Just too late, you may say... But now I have all necessary bits to hack one of mine A500 to internal 1 or 2Mb chip RAM without trapdoor expansion.:blink:
 

Tajmaster

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Not at all.

They are pretty common but may cost you. I bought a pair from a street electronic store who charges me R$10,00 for each chip(!) ( ~£3.50). What a robbery!:mad:

A few weeks ago a friend gave me other 12 of those chips...

Just too late, you may say... But now I have all necessary bits to hack one of mine A500 to internal 1 or 2Mb chip RAM without trapdoor expansion.:blink:

Ouch thats a bit steep! Errr, I think Ill leave it unless some pop up at a giveaway price!! LOL

Thanks for you help anyway mate (y)
 

rkauer

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Don't give up. Those chips are very easy to find. Some ancient Trident ISA cards have 4 or 8 of those and all you need is search in hardware landfills to find one.

BTW: you need 4 chips for each 512kb of Amiga RAM. Without a little as 512kb the card will be dog slow...

BTW2: you need to upgrade the ROM, good sir. 6.1 is rather ancient. Look for someone who can burn a v7 for you.
 

TjLaZer

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Ahh, thanks for the info rkauer :)

Are the chips for the 2091 hard to come by? I was thinking if its just a few quid for them then I might as well upgrade it.

I think there is a later ROM version too, V7 if Im not mistaken, are these hard to come by too?

Ive already got a GVP in my main A2000 but I thought Id try do what I can with the hardware that I have :)

I hit a PC Recycle yard and found a bunch of AS IS ISA cards with 1 or 2MB on them and those were the right kind and it worked great on my A2091.
 

chiark

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Taj, I seem to have 5 of these for no adequately explainable reason, which is no use to man nor beast - I think they're spares from an expansion that died... There's quite a few available on ebay from the US for around $2 a chip if that helps?

Have a look through old ISA video cards as these typically have this sort of memory on them.

Also, 501 ram expansions (and similar) will use these chips, so if you can find one of those for 99p then that'll have 4 on it.
 

rkauer

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Only the 4 or 5-chips A501 model have this chip on it.

Old model with 8 or 9 don't.
 

Tajmaster

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Thanks for the help guys, Im on the hunt for the chips (not the type from the chip shop, Im fat enough!).

@ Nick and rkauer

Are the A501 chips socketed?

I dunno if I have an old ISA card, I think I may do, Ill have a look later tonight :)
 

rkauer

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A501 have soldered chips, you need to desolder them and do a clean afterwards to be able to socket them in the A2091.
 

AndyLandy

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I have an ancient ISA graphics card with eight socketed RAM chips

graphicsram.jpg


Not sure if they're the right thing, but you can have the lot (including the card) for the cost of postage. It's no use to me, and I'm always happy to see PC hardware die to save Amigas. :)

Maybe rkauer or one of our resident experts can confirm if they're any good. :)
 

Tajmaster

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I have an ancient ISA graphics card with eight socketed RAM chips

graphicsram.jpg


Not sure if they're the right thing, but you can have the lot (including the card) for the cost of postage. It's no use to me, and I'm always happy to see PC hardware die to save Amigas. :)

Maybe rkauer or one of our resident experts can confirm if they're any good. :)

Hey Andy!

Thanks for the offer dude :) Ill certainly take you up on it :) PM me the cost of postage and Ill paypal it to you.

Does anyone know how much ram these 8 chips give me on the 2901? Is it 1MB?
 

AndyLandy

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I think they're 256k each, so total of 2MB.
 

AndyLandy

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Nope!

256kb x 4bits = 256kb each pair.

Ahh yes, of course. I should have remembered that you can't judge the size just by looking at the numbers. The number of 4MB SIMMs I bought on eBay that were described as 32MB -- "It says 1Mx32 -- it must be 32MB"
 

AndyLandy

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@Tajmaster

The card is in the post and on its way to you. Given the postage only came to 76p, it's hardly worth the effort of fiddling around with PayPal. Yours for entirely free. :)
 
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