Designed to recycle leftover 72pin 16MB memory cards in your stock. If you have a Mac with a 72pin memory socket, you most likely want to use 32MB or 64MB... If you have a lot of Mac collections, the 16MB that is wasted is often left in the drawer.
It's little hard to get a 30pin 4MB memory card now, but there are many models that can use it, so you may need a lot. In lower-priced models such as ClassicII, ColorClassic and LC, you can install two of these 4MB RAM cards to reach maximum memory capacity.
In SE/30, 16MB memory can be made 128MB with 8 cards, but in reality, 128MB is rarely used. Four 4MB cards will be 16MB and 32Bit addressing is possible. If you install 8x 4MB cards, it will be 32MB and you will be able to run a lot of softwares.
Advantages of recycling 72pin cards
Vintage DRAM chips are distributed as recycled chips by Chinese recyclers, but they are not necessarily removed from 100% working products, and there are many counterfeit chips that have the same shape and only the silk screen has been repainted... Therefore, the point is to reuse the 72pin SIMM you have at the time. This can be checked with an actual Mac that has a 72pin socket before stealing the part, and the chip can be peeled off from a working product and reused, so if it doesn't work, it's just a soldering mistake.
The best donor 72pin card is a 16MB configuration with 8 DRAMs and 4 parity RAMs. Of course, even if the card only has 8 DRAMs w/out parity RAM, you can add this later.
New design initiative
First, we can confirm that this 3-chip 4MB memory card was originally designed by Apple and has an old 1986 stamp. However, many hardware geeks are now making copies of similar cards. Of course, they follow the design that Apple made at the time, and I think you can easily find them on github. However, they are old in design, sometimes difficult to solder, and the finish is not beautiful. The downsides of those card designs are:
(*The downside is just my personal opinion and not meant to attack the designers. I would like to emphasize that I always admired these pioneers. Thank you):
- The through-holes (via holes) are large, and probably the design of the software used is old, so they are not solder masked. Therefore, when soldering is performed manually, the solder flows into the through-holes. *Currently, there is technology to drill smaller and more efficient through-holes.
- Since the through-holes overlaps the pad, solder bridging is easy. Also, the shape of the pad becomes distorted when soldering is completed.
- The foot print's pad areas are small, making it difficult to solder. The size of chip capacitors and chip resistors is small.
As mentioned above, I was personally dissatisfied and wanted to make a perfect card. With new programs and a sophisticated factory to manufacture the PCBs, you'll be happy with how the cards turn out. My design eliminates the above drawbacks and adds more features:
- Completely soldermask vias to reduce corrosion. The size of the via holes are 0.2 mm, which is the minimum required. Pads and through holes are separated.
- The size of the chip parts is slightly larger called 1206, making it easy for amateurs to work with.
- The area of the SOP chip foot print is slightly widened to make soldering easier.
- Equipped with LED so that +5V power can be confirmed for each memory slot.
- The card edge pad has rounded corners and is beautiful and hard to peel off.
- Although it is a 2-layer PCB, the router is placed so that it can take a lot of ground fill.
- Cost reduction and ease of production are realized by making it possible to cut 4 pieces as one PCB by hand
- A cool silk screen with a novel and new impression.
Compatible DRAM chips
If it is a 16MB 72pin SIMM with 8 chips (+4 chip parity) configuration, conversion is possible. These are also frequently used in 5V DIMM 64MB RAM cards (featuring 32 DRAM chips). If you look up the chip part number online and confirm that they are 4Mx4 DRAM chips, they should perform very well!
Confirmed usable 4MB DRAM chips are:
*Last update, AUG 27, 2026
- GM71C17400 (GoldStar), FPM
- HIT5117400 (Hitachi), FPM
- M5117400 (OKI), FPM
- K4F160411 (Samsung), FPM
- M5M417400 (Mitsubishi), FPM
- MCM517400 (Motorola), FPM
- M5M417409 (Mitsubishi), EDO
- TMS417409 (Texas Instruments), EDO
- MCM317400(Motorola) , FPM, Thanks to Bruce Rayne
- HYB5117400(Siemens), FPM, Thanks to Steve Fuller
- MN4117400(Panasonic), FPM
- Z417400(Texas Instruments), FPM
- KM44C4104(Samsung) , EDO
- 4217405(NEC) , EDO (*Apparently there are cases where the number string starts with "UPD", but my chip didn't have it.)
- GM71C17403(LGS) , EDO
- NT511740C0J(Nanya Technology), FPM
Read the memory chip conversion chart for compatible chips that work fine.
Dec 24,2022: SAMSUNG's KM 44C4100 is stated to be usable, but not only is it larger, but the outer width and pin-6 to 7 gap are different, so it cannot be used. So the diagram above is also incorrect. Correction here. Thank you.
Notice the outer width of the pin to pin, this KM44C4100J is 11.29mm, The gap between pin-6 to 7 is also not widely available. I don't think this big RAM chip is common, so it's not a big problem. But check before removing the RAM chip with heater.
About the Parity Chip
As those familiar with the configuration of this 2RAM chip know, the parity chip is optional. However, Few Macs does not work without Parity.
In my experience, my IIci from France(Euro specs) was the only one that needed Parity and wouldn't boot without Parity. This may be due to ROM.
Parity is not always necessary in almost of Macs, SE/30 or ClassicII etc…
Therefore, the minimum configuration of this RAM card works by soldering only 2 chips of DRAM and 2 capacitors.
The maximum configuration is 3 chips, 3 capacitors, 1 LED and 1 resistor.
The SE/30 has 32MB for 8 cards, which is practically enough memory. You can make this work in 32bit mode.
Available chips for parity:
514100 (Siemens HYB), 514100 (Hitachi HM), 71C4100 (GoldStar GM)
Parts that the user needs to prepare in addition to the kit
Other SMD parts for 4 cards:
SIZE Value Type Qty.
1206 0.1uF(100nF) 25V chip capacitor 12pcs
1206 330ohms resistor 4pcs
1206 chip LED* in your favorite color 4pcs
The above is an option with an additional 2USD in my store.
*Your own solder installation is required
Kit contents
Bare card x4 *1 board, which can be folded by hand like a KitKat!
*The 12 capacitors, 4 resistors, and 4 blue LEDs used for this are optional/ 2 USD.
At the end
If you had an SE/30, you would want to install a full 128MB of RAM, but if you had four SE/30s, it would be pointless to have all SE/30s at 128MB. However, if you use this kit, I think that you can increase SE/30 or Quadra700 with at least 32MB cheaply. With this card kit, you can make one card for 2 USD, so even if you make 8 cards, you will be quite satisfied with only 16 USD!
Mac Geeks around the world have made lots of DIY 4MB RAM SIMMs!