SN0420 belongs to well known collector Ron Jr.
I have my doubts about the serial number on this machine as no other Computer Space starts with a zero. I asked Ron if he was certain of the stamp on the serial plate and he says he double checked. Perhaps the original stamping machine did not punch the leading 1 (I am convinced this machine is actually 10420 as that follows the pattern of the other machines).
This machine originally belonged to Lloyd Thoburn of www.coinopwarehouse.com (perhaps this unit is the brother of SN9550?)