Where to get ZIP VRAM for NuBus Radius DirectColor video card

[bcl]

I have a DirectColor card with only the soldered-in 8 × 1 Mbit RAM (i.e., it's a DirectColor/8 with 1 MB VRAM). I would like to make it a DirectColor/24 with 3 MB VRAM but I can't figure out where to get ZIP VRAM chips. I presume nobody has made them for a long time, but does anyone know where there might be some NOS available?

 

[Kai Robinson]

Have you got a part number of the original ZIP chips that I can use to find a cross reference?

 

[bcl]

Have you got a part number of the original ZIP chips that I can use to find a cross reference?

Sorry, last week was horrible and I never got back to this. The factory-installed chips are Toshiba TC524256AZ-10.

 

[Kai Robinson]

Here are some - pricey though:

Pardon our interruption...

www.ebay.co.uk

These are a bargain for 3 pieces:

[3pcs] TC524256Z-10 1MBit CMOS Multiport DRAM ZIP28 TOSHIBA

1MBit DRAM + 512x4 SAM) CMOS M...

shop.tvsat.com.pl

Looks like almost all 1mbit ZIP28 RAM is 256k x 4-bit multi port DRAM.

OKI MSM514262 would also likely work.

 

[bcl]

Here are some - pricey though:

Pardon our interruption...

www.ebay.co.uk

These are a bargain for 3 pieces:

[3pcs] TC524256Z-10 1MBit CMOS Multiport DRAM ZIP28 TOSHIBA

1MBit DRAM + 512x4 SAM) CMOS M...

shop.tvsat.com.pl

Looks like almost all 1mbit ZIP28 RAM is 256k x 4-bit multi port DRAM.

OKI MSM514262 would also likely work.

These are Micron, but does it appear to be the same thing? I know less than nothing about DRAM that's not on a SIMM.

QTY (13) MT42C4256Z-8 MICRON 28 PIN ZIP 256Kx4 VIDEO RAM VRAM NOS 1 TUBE | eBay

13 PIECES MT42C4256Z-8 MICRON. NOS 1 TUBE. 256K x 4 VIDEO RAM. 28 PIN ZIP.

www.ebay.com

I'm going to ask the seller to confirm it's 13 of them for that price, because the photo shows 2 and it says 23 available. 13 seems like a strange quantity to be in a tube from the factory, but maybe these are repacked.

 

[Kai Robinson]

Most DRAM in the same packaging are the same type of DRAM - JEDEC defined pinouts at least. Very few, if any RAM manufacturers choose to ignore the JEDEC standards.

 

[bcl]

Most DRAM in the same packaging are the same type of DRAM - JEDEC defined pinouts at least. Very few, if any RAM manufacturers choose to ignore the JEDEC standards.

Well I ordered enough for the two video cards I could immediately find that use it and aren't fully populated. It should be here tomorrow. The price was by far the lowest I could find. Thanks for pointing me in the right direction, and we'll see if this works.

 

[bcl]

I added 16 ZIPs to the DirectColor/8 card. Before, Monitors control panel offered 256 colors. Now it offers Millions of colors (identifies as DirectColor/24). However, I did the same with a RasterOps 8L and nothing changed. The ROM on the Radius DirectColor card is labeled as "DIR. COL. 8/24," which suggests the card self identifies as one or the other based on how much VRAM is installed. The RasterOps ROM is labeled as just 8L, so it might need a different ROM chip to do 24-bit. On the other hand, one of the new VRAM chips might be bad or something else.