BETSI Expander for the Commodore PET

John Ball ball.of.john at
Mon May 8 19:35:34 CDT 2017

So it seems in the early days of the PET a company by the name of
Forethought Prouducts sold an expansion module called the BETSI which
plugged into the expansion bus of the PET and gave you four S100 slots. If
you google around you can find a flyer advertising the unit and optional
power supply and the owners manual which touches on assembly, component
locations and the schematics. It talks about adding sound voards, additional
video outputs, expanding ram and attaching directly to a larger S100 frame.
Beyond that I can find absolutely nothing else about it, much less a more
recent photo of one. Has anyone here ever used one? How practical were they
in reality? Suppose I went and built one. Does anyone have the PCB layout
templates so I could get a board etched or will I have to stick to the
schematic and build one by hand?


More information about the cctech mailing list