As the name suggests, this model came with 128KB memory. Replaced by the Macintosh 512K.
These are fairly highly sought after by vintage computing hobbyists as original 128K systems are harder to find. Many original owners upgraded to 512K boards to prolong the usefulness of the system, and original boards were likely recycled/destroyed at that time.
- MacRescue by Computer Care, gives you RAM slots and a SCSI interface
- http://www.ccadams.org/se/classicmac2.pdf - Classic Mac Repair Notes