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Hi everyone, My friend Garrett Fellers and I design, manufacture, and sell vintage hardware through his Garrett's Workshop brand. One of our products that's been out for a while is our GW4201-series "RAM2GS" RAM expansion card for Apple IIgs. (eBay...

As we all know, 68k Mac compacts have a hardware RAM limit of 4MB. However, there exist accelerators (e.g. Radius Accelerator 16) which extend the memory capacity to 16MB using onboard SIMMs. Presumably 8MB of this RAM is accessible in 24-bit mode. So my question is, what’s the typical memory...

Now that our Mac II ROM SIMM is almost finished, my friend Garrett and I are getting ready to move on to some of our future classic Mac projects. Next on the to-do list is our "ROMBUS" microSD interface for Mac Plus and 512K. One of our Mac Pluses is broken (E0122 SCR is dead), and the other...

Hi everyone, My friend and I recently made a batch of 2MB ROM SIMMs for the SE/30 and Mac II machines. We wanted a few of these ourselves as well as to sell through our little company (price will be $25 incl. domestic US shipping): We have also finished a design for an 8MB ROM SIMM (actually...

Hi 68kMLA, Maybe some people here remember my ARM-based "Maccelerator" proposal from a few years ago. I have cost-reduced the BOM for that project significantly and plan to get the hardware released soon, but that's not for today. Since the Maccelerator proposal, I have been working with a...

Title says it all. How do the NuBus cards which advertise QuickDraw acceleration do it? I've read much of Designing Cards and Drivers for the Macintosh Family, but there is no mention of video acceleration in there. Is the acceleration just some blitter functionality, where the card moves memory...

I have designed the basic architecture for an accelerator “system” which can be adapted to any 68k Macintosh with a PDS slot. The goals of the design were as follows: moderate cost at least 50x faster than Mac SE basic architecture can be used for any 68000, 68020, 68030 Mac with a PDS. Maybe...

In this first post, I will articulate my vision of accelerator cards for the SE and SE/30. What follows is a bit verbose, but hopefully this proposal will lead us to a finished product. I plan to start developing this thing in a few months. Right now, I'm trying just to gather more information...

I recently picked up 15 or 20 old Macs, including 4 compact models. I've now got an SE/30 that appears to be in great condition, but others are in pretty dire condition. Here's my SE/30. HDD doesn't work and I don't have a boot floppy, but the capacitors look okay and no battery acid on the...

I recently stumbled upon a collection of 68k Macs for sale: two Plus, an SE, an SE/30, along with 4 IIsi and 4 LC. Plus a few Apple IIGS, disk drives, etc. I'm a pretty experienced designer of PCBs, so I know how to inspect the condition of the logic boards and make sure the machines are in...

Hello all, First post here. :) I am trying to understand the video output circuitry of the later compact Macintoshes. I understand the Apple II's design... the RAM can run at twice the speed as the processor, so the video/DRAM refresh circuitry and the 6502 can interleave access to the...