> ... Can anyone tell me what chips go into Z18 and Z64? Those are the
> only other ones that seem to be missing

A copy of the service manual (including schematics) is available on-line
here:

http://www.rhodeschroma.com/?id=polarisservicemanual

There's also a copy of the parts list here:

http://www.rhodeschroma.com/?id=polarisservicepartslist

Z18 appears to be a 74LS244:

http://www.rhodeschroma.com/content/polarisservicemanual/polarisserviceschematics/computermemorydatapanelbuffersbattery.pdf

Z64 appears to be a noise generator chip (MM5837)

http://www.rhodeschroma.com/content/polarisservicemanual/polarisserviceschematics/addashcontrolnoisegenerator.pdf

David C.