Sharp ZQ-5000 Service Manual page 31

The ZQ-5000/5200 board units have different parts and different patterns according to production date. (The boards units, however, are
l
compatible each other.) in case of a board unit trouble in a set of the first production thru 10050th production, replace the whole board unit with
new one. (The parts codes of the component parts assembled in the board are not informed.)
From 10051 th production a new board unit is assembled to each set. The parts codes of the component parts in the new board will be
informed you later by Service Information.