Piltdown Man - Power Mac 6100 prototype
Piltdown Man is the codename for the Power Mac 6100, one of Apple's first PPC-based Macs. The Piltdown Man protoype is in a Centris case, the final shipping case being slightly modified, particularly around the floppy drive.
Note the non-standard port cutouts on the back.
The computer's name is "PDM," short for Piltdown Man. The processor is 50 MHz, a speed which was never used in a shipping Power Mac. The serial number is #000000136. Four megabytes of RAM is onboard, as oppose to eight megabytes in the shipping unit.
The motherboard is red, unlike the shipping unit which has a green motherboard. Several readers have emailed me and said that they also own prototypes of different colors, including blue and yellow. Apparently it is common practice at Apple to use boards of various colors in the prototyping stage.
This computer is owned by Hirohisa Yumoto, a Japanese collector of Apple computers.
Marco Maggiora provided images of his later Piltdown Man prototype:
From the looks of things, this prototype was intended for outside beta testers.
No label, of course. It's interesting to note that the tape used is the same as that on Hirohisa's.
Note that there are no icons above the ports. Additionally, this version had an auto-inject floppy drive and an 80 MB HD. It is dated March 2, 1994.