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Polyphloisboisterous '030

February 15, 2026
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...is my edit of the MicroMac Performer card for Apple's Macintosh Plus personal computer.
It's a CPU upgrade. It preempts the 8 MHz Motorola 68000 and replaces it with a faster 16 MHz 68030.
It's also my first PCB design.

Photo of Polyphloisboisterous '030

Click here to watch the YouTube video
Click here to see the GitHub repository
Click here to read the thread on 68kMLA forums

Performance

(Tested with Speedometer 3.23)

Timeline

My board is

Can I use this card in my Macintosh SE?

It would work, but the SE has an expansion card (PDS) slot which makes soldering a socket on top of the 68000 pointless.
For the SE I recommend this PCB here.
It looks like this:

Computer rendering of Performer SE board

What's a GAL? How do I program it?

Generic Array Logic or GAL chips are semiconductor devices that can be programmed with predefined digital logic functions.
Basically you can roll your own little logic chip.
Yes, you can program them with a TL866/T48 universal programmer. Those are expensive so I use a special Arduino hat called afterburner instead.
You need a PLCC-20 to DIP-20 adapter to insert PLCC packaged GALs (as used on these accelerators) into a programmer.
They look like this:

Photo of PLCC-20 to DIP-20 adapter

Can you program GALs for me?

Probably. Get in touch using an internetwork listed on the Ground Floor.
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