The XF86 configuration information and program is generally pretty good for setting up X-Window with multi-frequency monitors. But over the years, I have had occasion to use X-Window with fixed-frequency monitors, and found that things are not as straightforward.
One of these fixed frequency monitors is a 17 inch Hitachi monitor that was used with HP and NCD x-terminals. There does not seem to be much solid information on these, and I originally thought that they were tuned for 72hz vertical refresh and 1280x1024 resolution. This configuration did work, but the displayed area left a good portion of the screen unused. Using a vertical rate of 70hz seems to be just right, but getting all the synch settings just right was tricky, and took a while to get right.
Here is my XF86Config section for my NCD 17cr monitor:
Section "Monitor" Identifier "NCD/HP" VendorName "Hitachi" ModelName "cr15/1097" HorizSync 74.4-74.4 VertRefresh 70-70 Modeline "1280x1024" 125.00 1280 1300 1460 1680 1024 1040 1043 1063 EndSection
The manual gave the following specifications: resolution is 640 (horiz) by 870 (vert), 75.0 herz refresh, and 68.9khz horizontal frequency. Here is my XF86Config section for this monitor:
Section "Monitor" HorizSync 68-69 VertRefresh 75-76 Modeline "640x870" 54.5 640 657 752 791 870 874 878 918 EndSection
According to xvidtune, the actual pixel clock is 54.40, horizontal=68.90khz, and vertical=75.05hz, very close to the manufacturer's specs.