I suppose it depends on your definition of
'pc'. Pretty much everything
designed before say 1982 was free of custom logic AFAIK, this includes
(not
a complete list by any stretch) the Acorn System x and
Atom, Compukit
UK101,
Tangerine Microtan65, Sinclair ZX80, Grundy Newbrain
(an exception) etc.
All
'personal computers'.
Perhaps the (1982?) Husky Hunter
John