Having trouble finding the RAM for this GS Memory board.

[Hugh]

I have one of these (sorry for the external link): http://whatisthe2gs.apple2.org.za/ram-gs and I can't seem to find the ram for this board?

I downloaded the Manual and testing software and it tells me what it is, but when I put that in google I don't come up with anything that this card will take. Is this RAM board basically orphaned compared to the other RAM boards?? I mean is you can still buy RAM for the Apple Memory board and stuff. The board currently has 2mb on it now, My understanding it's upgradable to 4mb.

I am looking to sell this board, but I wanted to inform the potential buyer(s) of all info.

Thanks for any help!

=Hugh

 

[MacTech68]

What's the numbers/letters on the ICs ? Pic ?


LATE EDIT:

If I'm reading the manual correctly, the DRAMs are a 1Meg x 1bit each chip, in a ZIP-20 package.

There would be many different manufacturers each with similar part numbers. However, it looks like the suffix on the part is going to be important for TWO reasons.

1. The suffix on one manufacturer (Siemens) should be "BZ" to denote a ZIP-20 package

2. the last part of the part number should denote the refresh rate, eg -100 may denote 100 nano seconds, or -12 may denote 120 nano seconds.

If I'm correct then one manufacture's part number (Siemens) would be HYB511000BZ-xx (where xx denotes the required refresh rate which the manual does not state).

 

[Hugh]

Here is some pics of my card, but the chips? are black with no writing on them, and they are not normal IC (see picts).






A pic of my card. ^^^



Close up the where the chips go. ^^^


Thanks for any help!

=Hugh

EDIT: I just found some numbers: TC511001AZ-10?

 

[MacTech68]

EDIT: I just found some numbers: TC511001AZ-10?

Yup - that's a Toshiba 100 nano seconds in a Zip-20 package

So, at least there is two parts:

TC511001AZ-10

HYB511001BZ-70 (only available in -70 -60 -50) WHOOPS - NOT Nibble Mode

 

[Hugh]

Forgive me here.. What part number should I be looking for this card then? The two banks are soldered to the board and can not be removed. So I need to get the chips that match the ones that are already there correct?

Thanks sorry this type of IC is got me all confused.

=Hugh

 

[MacTech68]

Please confirm that the part number you gave is printed on the chips on YOUR board, as it denotes Nibble Mode RAM. As such, please ignore the other number I gave previously.

The manual does NOT state if standard FPM DRAM can be safely used.

Yep - the board was supplied half or fully populated.

Maximum is 4Mega Bytes, so:

8 pieces of a 1Mega Byte, 1 bit chip = 1 Mega Byte (for an 8 bit machine).

so, they are all 1Mega Byte, 1 bit DRAMs.

I'd be going with the 100 nano second DRAM (if you can find them) since if the memory speed is too fast it may drop bits due to the slower refresh of the card.

Quite a few manufacturers made these and will have slightly different part numbers but these chips whilst short lived in production were a standard appearing on many devices at the time.

The description would be:

"1Mx1 Nibble Mode DRAM Zip-20 100ns"

So, that gives me:

KM41C1001BZ-10

MB81C1001A-10LPSZ

TC511001AZ-10

MT4C1025Z-10

 

[Hugh]

MacTech, Sorry I'm just now seeing your edit.

Yes that is the number on those chips and they are soldered to the board. I had no problem with the board, it's just that I upgraded to a brand new board that uses SIMS with 4mb on it with a smaller foot print.


=Hugh

Please confirm that the part number you gave is printed on the chips on YOUR board, as it denotes Nibble Mode RAM. As such, please ignore the other number I gave previously.

The manual does NOT state if standard FPM DRAM can be safely used.

Yep - the board was supplied half or fully populated.

Maximum is 4Mega Bytes, so:

8 pieces of a 1Mega Byte, 1 bit chip = 1 Mega Byte (for an 8 bit machine).

so, they are all 1Mega Byte, 1 bit DRAMs.

I'd be going with the 100 nano second DRAM (if you can find them) since if the memory speed is too fast it may drop bits due to the slower refresh of the card.

Quite a few manufacturers made these and will have slightly different part numbers but these chips whilst short lived in production were a standard appearing on many devices at the time.

The description would be:

"1Mx1 Nibble Mode DRAM Zip-20 100ns"

So, that gives me:

KM41C1001BZ-10

MB81C1001A-10LPSZ

TC511001AZ-10

MT4C1025Z-10