Zip Ram - A3000 - Specifications?

[jiffydos]

Hi All...

Big questions...

Amiga 3000 Zip ram.

I have heard so many different theories that I figured I would bring it to you.

As I thought I understood it, 1Mx4 Zip Ram would be 4Zip chips equals 1MB, which would mean that you could only put 8MB of ram in the 32 slots on the A3000.

Can someone please clarrify this for me?  Because, everything I see says that it can have 16MB of zip fast ram.

[alexh]

1Mx4 Zip RAM means that 1 chip is 4Mbits or 512kbytes.

4 chips would be 2Mbytes.

32 * 4Mbits = 16Mbytes.

Think about it as rows and columns. 1Mbit deep by 4 bit wide.

[jiffydos]

Ah!  That makes sense!  

Thanks!

[CatHerder]

4x256 = 8 chips per MB (4MB per 3000)
1x4 = 2 chips per MB (16MB per 3000)

A3000 zipdram sockets = 32
A3000 zipdram chip sockets = 16 (2MB / 16 4x256k)

They're not as rare as everyone thinks -- the problem is finding the right part number for the 1x4 zips (nobody lists them by name in their parts catalogues, they're all listed by manufacturer and part number).

For example: if you want MCM54400AZ80 (which are 80ns 1X4 zips) you'd search for that and find that there are 1000 of them available through 1-source  . The issue here is, 99.99% of all the sources you will find for your specific zipdram part numbers are wholesalers and suppliers and you have to order at least $250 worth of anything to get an order. (which is fine if you're a reseller)

Another search for OKI M514402AZ-80 (I dropped off the AZ-80 to widen my search) resulted in me finding 23 70ns chips, 180 514402A-80Z chips (which I know are 1x4 80ns zips for A3000's or supra ram expansions - I just don't "know" if they're static column etc), and 450 514402B 70ns chips (not positive which flavour of zips these ones are) from AAT-Technology. I'm pretty sure most of these are the right animals because the mf dates on the chips range from 90 to 94.

It's all about knowing what you are looking for, and not about knowing what the part is called "on the street" :-)

In cases like this Amiga.org website -- it would be extremely beneficial to the average user if other Amiga 3000 owners took the time to list the part numbers on their ZIP ram so other 3000 owners (and stores) could source the parts themselves. (I used to do this, but I am getting out of all my Amiga inventory so I figure why not share the knowledge.) I know I've seen at least 20 different part numbers for 1x4 zips used in 3000s, I just happen to know two part numbers because I have them sitting here (both with a broken leg or I'd offer to ship them to you for nothing).

[jiffydos]

That's awesome help!  Maybe I'll actually be able to find them now.

Do you know, is 80 as fast as I can use.  Can I use 60s?  Will it help?

[CatHerder]

You can use 60 or 70 or 80. Just don't mix them in an A3000 or you'll have all sorts of mysterious errors. I used to get little glitches randomly on my screen because of a single 80 getting mixed in with a bank of 70ns ram. I recall taking about 2 days to track down what the deal was way back when. (We all blamed Amber, and replaced it, but that didn't solve the problem, finally noticing that one different zip and changing it solved it after a whole lot of cursing and fist shaking.) :-)

Stick with all 70ns (they're the most common next to 80ns that I can find).

Although, you might be able to mix 80's and 70's if you pair them in different banks. From what I recall you want to fill bank 0 first, then 1 then 2 then 3. If you are missing a chip in bank 2 you won't see the ram in bank 3 (unless I recall incorrectly). The 3000 (and 3000T) motherboard needs to have the RAM populated bank at a time (you can't just shove ram in the bottom 8 sockets and expect to see it all or be able to use it all).

[jiffydos]

Very cool...

Lots of info.  

The search continues!  

[Chain]

mine A3000T (in avatar, yup :-)) have mixed two manufacturers:

NEC JAPAN
D424402V-70  :-o
9130FU004

and

HM514402A28  :-o
JAPAN
and there is also "Toshiba" written , but im not 100% sure
(call me halveblindy)


who´s next?

[Zac67]

[51|41|42]4402 are static column (SC)
xx4400 are fast page mode (FP)

Static column enable an '030 to burst, so will be slightly  faster (2-5%). You can't mix SC and FP unless you put FP on the first bank (which is tested on POST to determine burst capability). AFAIK an '040 (on A3640) can't burst anyway, so SC or FP shouldn't matter.

Mixing different speed grades usually doesn't cause problems but mixing different manufacturers/types might. If you have to mix, it's advisable to put the slowest RAMs onto the first bank and the slowest chips on lower bits, i.e. to lower left hand side (when seen from front). When mixed TEST YOUR RAM!

[gdanko]

Can someone please clarrify this for me?  Because, everything I see says that it can have 16MB of zip fast ram.

You can... look at this whichamiga shot from my 3500 (3000T proto)

http://www.streamload.com/s00p/amigas/A3500/3500_WhichAmiga_Closeup.jpg

It has 16 MB in ZIPs.

[CatHerder]

gdanko wrote:

You can... look at this whichamiga shot from my 3500 (3000T proto)

http://www.streamload.com/s00p/amigas/A3500/3500_WhichAmiga_Closeup.jpg

It has 16 MB in ZIPs.

Super, but what are the part numbers of the RAM so others can benefit by being able to search for some. :-)

[JimS]

Here are a couple pages from Commodore's tech notes on 'approved' part numbers for various products, including the 3000.

[img=http://img364.imageshack.us/img364/6149/cbmokram016py.th.jpg]


and.....

[img=http://img307.imageshack.us/img307/9072/cbmokram024ym.th.jpg]

[Chain]

My friend Alcone have in 3000D:

D424402V-70
9105XU602
NEC JAPAN

and couple of

TOSHIBA 9241HCK
TC514402AZ-70 JAPAN

and

HM514402ZP8
JAPAN 9048
R2002NN

from other machine from germany

[koaftder]

my zips are all:

OKI
M514402B-80Z
40655029A9Z

@ cat herder:
Thanks for posting that info on the ram