5 Oct
2015
5 Oct
'15
11:52 a.m.
Look for inconsistencies in voltages and pulses to and
from RAM. You may
need RAM at the lowest memory locations to boot. Hooking up the keyboard
at least to eliminate a missing keyboard as a reason the system does not
The PET keyboard is just a matrix of switches, if nothing it pressed it tests as
an open-circuit between all pins. So the machine can't fail to start up because
the keyboard is not connected.
-tony