This is a link to a copy of the MK14 manual for early versions of the MK14 including the schematic. It documents the "original" monitor that resets to "---- --" as well as the schematic showing the PROM decoded only by the A11 signal, as was the case with early boards.
https://drive.google.com/file/d/1C32...ew?usp=sharing
I'm pretty sure I've got the sharing options correct....!