Amiga 3000 ZIP ZIG ZAG 320 pin ram sockets

A3000T · Apr 25th 2023

Jens

Or anyone!

I picked up a A3000T in much need of repair. I have been able to get it running by install my MK2 68060-50 and it does boots. But the ram sockets are bad and need to be replaced.

I can get a ZIP to SIMM adapter board for the Amiga where I can install 2 4meg SIMMs, it is made to plug in to the onboard ZIP sockets but there is an interference issue that I can't install my MK2 expansion board the SIMMs are in the way. I can replace all sockets with 20 pin machined gold plated inline sockets or I can solder all 1x4meg ICs directly on the mother board.

Anyone know where I can get 2 RAM sockets bank 0 and bank 1 for the A3000D/T motherboard. These are 320 pin ZIP sockets each. I would like to get it as original as possible.

Jens · Apr 25th 2023

How about adding Fastmem with a BigRamPlus (Z3 card)?

A3000T · Apr 25th 2023

Jens

Sorry but I'll pass, at 130 pounds plus vat and tax and shipping $180 is a bit expensive. I need to remove the ZIP sockets anyway to be sure all the traces are ok I know that there are 640 pins I need to unsolder but I have a good desoldering station. I have 10 megs of ram on hand I can solder them to the board, and it will only cost me my time. I may be able to use the ZIP 2 SIMMs board, with the ZIP sockets removed there may be enough clearance so CN606 32bit slot does not have clearance issue, there's no program that I have that needs more than 8 megs. My a3000T is working just fine with 74 megs. The second A3000T is one that I picked up at a yard sale for $30 with keyboard, mouse, 3 joy sticks and a bunch of software, games and a CyberVision 64/3D graphics card. So now I have 2 A3000T, 1 A3000D and 1 A1200.

MAGA (Make Amiga Great Again, Spread the Word!

thebajaguy · Apr 25th 2023

On my one A3000D, it had a hacked ZIP-2-SIMM solution with tons of ~4" wires to offset it for accelerator use - from the past owner.

I chose to remove it all, and put the (albeit different memory solution) 16MB ZIP-2-DRAM board (a limited run AmiBay offering) directly on the motherboard where the ZIP sockets are. It's flush with the motherboard. and very neat, allowing much more airflow through the region. I still have that crazy ZIP-2-SIMM board with all the wires... in a box.

I'd suggest you go with the ZIP-2-SIMM board directly to the motherboard. If you are worried about clearance, make sure you trim all the pins on the ZIP-2-SIMM back side, and a thin clear plastic separator similar to what is under the motherboard next to the shield. That would let you not use the plastic separator common to most header strips. You might get away with just using the longer side of a pin strip header.

And as for the BigRAM+, it's a reasonable solution when there is no other option, but it's also on the other side of Buster, and well, we still need a better Buster before the BigRAM could perform as well as CPU-side RAMSEY memory. We keep hoping that project might one day continue to happen.

A3000T · Apr 26th 2023

Jens

Thanks for your very useful information. Good idea about using thin plastic to insulate the boards, but I need to get the ZIP sockets off first which is going to be a long job, 640 pins to unsolder and make sure each and every pin is free and floats, I don't want to lift any traces.

I don't think that there will be a new RAMSEY or BUSTER chip for the old Amigas. MOS/CSG is no longer around and where software doesn't have hardware overhead it's just time to wright the code. Designing the new IC's then you need test them, then to outsource to fab the ICs. and how many are you going to make 1000, 2000 what's the market, and the price per IC $100, $200. I have RAMSEY rev 7 in my A3000T but the A3000D has rev 4 and I don't know what the difference is, I know it's an improvement over the rev 4 but I haven't checked in to it, but I will.

Frank

thebajaguy · Apr 27th 2023

My comment regarding Buster is related to a project mentioned prior to the pandemic/chip shortages for certain CPLDs/FPGAs on the market. A certain famous engineer of the Amiga Buster chip was looking into possibly redesigning something new/replacement for Buster - and finish the work that couldn't be finished due to C='s financial state back in the early 1990's. It's all on hold, though, until a viable supply of parts can be secured, and also fully redeveloped and tested. With reprogrammable parts, though, the high cost of classic chip-fab is no longer there. I'd say there's a decent market for an improved Buster if one might get produced.

As for the ZIP sockets coming out, that would be a bit of slow and steady work. I might suggest a lighted magnifying glass on an arm. I also invested in a desoldering unit, but I still use the manual suction tube method. You will want to add modern solder to each pin before you vacuum it out. The solder you use today and what they used for wave soldering back in the day has slightly different properties. It's easier if you add a little before extracting.

If you have a RAMSEY-07 in the A3000T, then it's paired with the unobtanium chip known as SDMAC-04, which is an ideal combo. Look for the Dave Haynie notes on the Buster/SDMAC - they are online. Alas, if you have the A3000D with the RAMSEY-04, it needs to be paired with the SDMAC-02. It's generally fine for stock systems. It can have some issues with some accelerators' load on some signals, and you would want a Buster-11 if you have any Z-3 cards.