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Reimplementing the BBU has been a much-discussed topic on here. Whenever it comes up, I always suggest that we should be focusing not on a form and function replacement for the BBU but a redesigned Mac SE motherboard using modern RAM and FPGA to implement the BBU and RAM. Thanks to @Kai Robinson...

Anyone have a source for the PDS connector used on a Quadra 700, 900, 650, and 800 PDS slot card? According to the Quadra 700 dev note, the connector you put on a PDS card is a KEL 8807-140-170LH. Can’t find that anywhere for a reasonable price. I see some discussion on 68kMLA where one...

Here's my latest design for a Mac IIfx RAM SIMM. As always, it's a collaboration with Garrett Fellers and open-source even for commercial use if you remove the Garrett's Workshop trademark. Now, unfortunately I don’t have a IIfx so I will need some help testing these once I get em. My rule is...

I'm trying to add the onboard Ethernet to my Centris 610 which didn't originally have it. In order to do this, I have to burn the 82S123 32-byte “Ethernet ID ROM” that contains the machine's MAC address. Can anyone who has a Centris with Ethernet post the contents of their Ethernet ROM so I can...

I have been burned by “popcorning” both in my repair work and also in small production runs too many times and now I almost always desiccate populated boards and parts at 80-100 Celsius for 24-48 hours before hot air rework or reflow soldering. Does anyone else do this? In my experience, the...

The Mac IIsi motherboard is wired for a 1 MB onboard RAM array using eight 256kx4 DRAM chips or a 4 MB RAM array using eight 1Mx4 chips. After discovering this on my broken IIsi, I was able to simply replace the eight RAM chips with larger 1Mx4 RAMs (e.g. KM44C1000, M5M44400, MT4C4001) and get 4...

Has anyone tried piggybacking another set of VRAM chips on top of the ones already mounted on the motherboard? On the 840AV, most of the signals are shared between the soldered VRAM and expansion VRAM. The only different pins are separate /RAS and /SE lines on the CIVIC video chip which are...

Here's one of my favorite resources on car dynamics which I read and re-read many times as a Honda-obsessed teenager: https://www.autozine.org/technical_school/tech_index.html The author, Mark Wan, describes the site best himself: The material on this site basically taught me the principles...

Hi everyone. I’ve got another nearly finished project here. This one almost done! I have boards in hand and they have been working in the lab for almost 6 months. I need some testers who have a variety of Apple II family machines to test the cards out on. For those who don't know, "Slinky" or...

Kai's Mac Classic Reloaded is exciting! I have some chips from bombed SEs which I am anxious to put to use once I have a bit more time and space on the soldering bench. But I feel it would be a big shame if the project sort of went out the door with the original RAM card when we can make...

One of the next steps on my rather tentative ESP32-based network card concept is to figure out what API an Ethernet card has to implement. I haven’t dumped the list of device drivers on one of my Macs with NuBus Ethernet but I suspect that Ethernet driver puts an entry in the system device...

The accelerator I posted about yesterday is a bit advanced so I figured I'd finally do a schematic for an idea I've had for a while. This one is more softwarey and there are a lot of great software developers out there so hopefully we can get some kind of collaboration going. One of the things...

Hi everyone. I wanted to post about my new design for a 25 MHz 68HC000-based Macintosh SE accelerator. As usual with my gizmos, this is a collaboration with Garrett Fellers of Garrett's Workshop. I'm the principal designer and Garrett is the codesigner and he manufactures our boards. My aim...