1540/2031 schematic error?

From: Francesco Messineo <*francesco.messineo_at_gmail.com*> Date: Tue, 20 Feb 2024 10:12:53 +0100 Message-ID: <CAESs-_wRBTdkxrvGxExMakLx_m-Sx9FYfsdt-uvf=JECWOpMfA_at_mail.gmail.com> · francesco.messineo_at_gmail.com

Hi all,
I think there's an error on both the 1540 (1541 long board) and the
2031 (both HP and LP).
Input pin 9 of 74LS191 U5L (on the HP schematic, 1540/LP is a
different position) isn't shown.
I *think* it should be grounded but I don't have any long board or
2031 to confirm. Can anyone check on the real hardware?
I was curious to understand why they used this LS191 instead of the
LS193 (that's already present in different circuit parts) and  pin 9
could be why, if it's not grounded.
Any help is welcome.
Frank IZ8DWF