Resources
Wiki
everymac.com
lowendmac.com
Schematics
Internals
Motherboard
Memory
This is 4x4MB RAM, huge comparing to other models of the time.
Power Supply
Sony APS-06
Floppy Disk Drive
Sony MP-F75W-11G
Hard Disk Drive
This is not the original drive for Macintosh IIsi, the original drives were 40, 80 or 160MB large. This is also not an Apple branded drive and needs to be initialised using a patched version of the disk tool.
1080MB, IBM DPES-31080