Amiga 3000 ZIPs DRAM solution ?

[Amiduffer]

I have a question about A3000 Fast Ram.

Below the ZIP slots, are sockets for DIP style memory chips, that if filled, will get you up to 16megs. Has anyone ever found any of those or have they dissapeared off the face of the earth?

[Amiduffer]

WRONG!

As long as you put the same type of chip in the ZIP and DIP sockets, you CAN have chip in both type of sockets. As a matter of fact, you will notice that some ZIP sockets have the same UXX numbers as the DIP sockets. That's because they are connected together.

DIP sockets on the fast RAM of the MoBo can accept both 256x4 or 1Mbitx4 chips and fast page mode DRAM chips of both capacities exist in both ZIP and DIP packages.

As long as you don't populate both sockets having the same number and you use the same types of chips, you're okay.

I know so... I did exactly that in my first A3000 15 years ago. It's first 4MByte was 8 1Mbitx4 DIP chips and the last 12MBytes were ZIPs. I did this because DIPs were cheaper than ZIPs.

So, to answer Amiduffer's question: There are 32 ZIP sockets in the 3000's fast RAM section AND 8 DIP sockets. The 8 DIP sockets are just "clones" or "reconnected versions" of the 8 first ZIP sockets. So, if you want 16Mbytes in a 3000, you can either have 32 ZIP chips of 1Mbitx4 or 8 DIP chips of 1Mbitx4 and 24 ZIP chips of the same capacity. Just make sure the part number on your DIP and ZIP chips are the same.

Cool. Too bad DIP memory chips are harder to find than ZIPs.