The Macintosh IIsi was a midrange model from late 1990 meant to go up against PC clones in business environments. But some of the compromises that its engineers had to make to hit its price point meant for some very interesting quirks.
Brahcnus Creations: https://www.recapamac.com.au and https://www.youtube.com/branchuscreations
BlueSCSI: https://www.bluescsi.com
Hakko FR-301 desoldering iron (affiliate link): https://amzn.to/3mNuER6
Sources:
MacUser, December 1990.
"Can new Macs restore shine to Apple's future?," Computerworld, December 24, 1990.
IIsi NuBus adapter card photo: https://www.recycledgoods.com/apple-820-0303-02-nubus-adapter-card-for-iisi/
IIsi NuBus adapter card scan: https://www.applefritter.com/node/2076
DayStar dual-socket PDS and cache card riser photo: https://www.applefritter.com/node/10199
"Mac IIsi," Macworld, December 1990.
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Music by Soundstripe (https://www.soundstripe.com) and Epidemic Sound (https://www.epidemicsound.com).
Intro music by BoxCat Games (https://freemusicarchive.org/music/BoxCat_Games).