Okay,

I still did not understand the problem itself,
and you probably do not know how my arduino stuff exactly works.


My arduino stuff listen to (reads that) the 4 bit input side of the IC26(74LS145) and writes the 8 bit input side of the IC27(74LS373).

So it does not touch the 10 bit output of the IC26.


Knowing this, maybe I do not have to use diodes after all ?

If so, you really do not need diodes.

Hurrah !

PS. Sorry for the delay, but somewhere I escaped this post

Do not feel sorry ... Thanks for the reply at any time ...