I have a Hitachi CM823F, not listed in /usr/share/hwdata/MonitorDB.
I've downloaded mon_inf.zip from the URL listed above which contains
the Windows INF file for this and many other models. There's also a
hitachi_inf.zip for some other models. Here's direct links to both:
Based on looking at another Hitachi model for which MonitorsDB has an
entry, I concocted this entry for the CM823F using its INF file:
Hitachi, Ltd.; Hitachi CM823F; htcb3f7; 31.0-121.0; 50.0-160.0; 1
Added in 1.105-1