Macintosh IIsi Developer Note
Download it here: Macintosh IIsi Developer Note.pdf
This is Apple Computer's own developer documentation for Macintosh IIsi, published in 1990. It covers the IIsi's single expansion slot and its NuBus and 030 direct-slot adapter cards, the 68HC05 ADB microcontroller and the soft-power circuit, the +5 V trickle supply that keeps the real-time clock and parameter RAM alive with the machine switched off, and the video and sound subsystems.
Apple's developer notes are a different document from the Service Source repair manuals: the Service Source tells a technician which module to swap, while the developer note gives the electrical and architectural detail — rail currents, connector pinouts, power budgets and chip functions — that a repairer needs in order to make a go/no-go measurement. Several figures on this wiki are cited to this document.